因为工作需要，可能我离前端走远了，偏node方向了。所以异步编程的需求很多，于是乎，不得不带着学习async了。
我有个习惯，用别人的东西之前，喜欢稍微搞明白点，so就带着看看其源码。
github: https://github.com/caolan/async
文档：http://caolan.github.io/async/
里面提供的工具方法，控制流程方法还是很多的。所以需要哪些方法，就看相应的源码。
下面是其全部源码。
(function (global, factory) {
typeof exports === ‘object‘ && typeof module !== ‘undefined‘ ? factory(exports) :
typeof define === ‘function‘ && define.amd ? define([‘exports‘], factory) :
(factory((global.async = global.async || {})));
}(this, (function (exports) { ‘use strict‘;
// 重写数组中的slice方法
function slice(arrayLike, start) { // arrayLike: 类数组对象 start: 开始位置
start = start|0;
var newLen = Math.max(arrayLike.length - start, 0); // 长度
var newArr = Array(newLen); // 创建一个长度为newLen的数组
for(var idx = 0; idx < newLen; idx++) {
newArr[idx] = arrayLike[start + idx];
};
return newArr; // 返回数组
}
var initialParams = function (fn) {
return function (/*...args, callback*/) {
var args = slice(arguments);
var callback = args.pop();
fn.call(this, args, callback);
};
};
/**
* Checks if `value` is the
* [language type](http://www.ecma-international.org/ecma-262/7.0/#sec-ecmascript-language-types)
* of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String(‘‘)`)
*
* @static
* @memberOf _
* @since 0.1.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is an object, else `false`.
* @example
*
* _.isObject({});
* // => true
*
* _.isObject([1, 2, 3]);
* // => true
*
* _.isObject(_.noop);
* // => true
*
* _.isObject(null);
* // => false
*/
function isObject(value) {
var type = typeof value;
return value != null && (type == ‘object‘ || type == ‘function‘);
}
var hasSetImmediate = typeof setImmediate === ‘function‘ && setImmediate;
var hasNextTick = typeof process === ‘object‘ && typeof process.nextTick === ‘function‘;
function fallback(fn) {
setTimeout(fn, 0);
}
function wrap(defer) {
return function (fn/*, ...args*/) {
var args = slice(arguments, 1);
defer(function () {
fn.apply(null, args);
});
};
}
var _defer;
if (hasSetImmediate) {
_defer = setImmediate;
} else if (hasNextTick) {
_defer = process.nextTick;
} else {
_defer = fallback;
}
var setImmediate$1 = wrap(_defer);
/**
* Take a sync function and make it async, passing its return value to a
* callback. This is useful for plugging sync functions into a waterfall,
* series, or other async functions. Any arguments passed to the generated
* function will be passed to the wrapped function (except for the final
* callback argument). Errors thrown will be passed to the callback.
*
* If the function passed to `asyncify` returns a Promise, that promises‘s
* resolved/rejected state will be used to call the callback, rather than simply
* the synchronous return value.
*
* This also means you can asyncify ES2017 `async` functions.
*
* @name asyncify
* @static
* @memberOf module:Utils
* @method
* @alias wrapSync
* @category Util
* @param {Function} func - The synchronous function, or Promise-returning
* function to convert to an {@link AsyncFunction}.
* @returns {AsyncFunction} An asynchronous wrapper of the `func`. To be
* invoked with `(args..., callback)`.
* @example
*
* // passing a regular synchronous function
* async.waterfall([
* async.apply(fs.readFile, filename, "utf8"),
* async.asyncify(JSON.parse),
* function (data, next) {
* // data is the result of parsing the text.
* // If there was a parsing error, it would have been caught.
* }
* ], callback);
*
* // passing a function returning a promise
* async.waterfall([
* async.apply(fs.readFile, filename, "utf8"),
* async.asyncify(function (contents) {
* return db.model.create(contents);
* }),
* function (model, next) {
* // `model` is the instantiated model object.
* // If there was an error, this function would be skipped.
* }
* ], callback);
*
* // es2017 example, though `asyncify` is not needed if your JS environment
* // supports async functions out of the box
* var q = async.queue(async.asyncify(async function(file) {
* var intermediateStep = await processFile(file);
* return await somePromise(intermediateStep)
* }));
*
* q.push(files);
*/
function asyncify(func) {
return initialParams(function (args, callback) {
var result;
try {
result = func.apply(this, args);
} catch (e) {
return callback(e);
}
// if result is Promise object
if (isObject(result) && typeof result.then === ‘function‘) {
result.then(function(value) {
invokeCallback(callback, null, value);
}, function(err) {
invokeCallback(callback, err.message ? err : new Error(err));
});
} else {
callback(null, result);
}
});
}
function invokeCallback(callback, error, value) {
try {
callback(error, value);
} catch (e) {
setImmediate$1(rethrow, e);
}
}
function rethrow(error) {
throw error;
}
var supportsSymbol = typeof Symbol === ‘function‘;
// 是否是异步
function isAsync(fn) {
return supportsSymbol && fn[Symbol.toStringTag] === ‘AsyncFunction‘;
}
// 包装成异步
function wrapAsync(asyncFn) {
return isAsync(asyncFn) ? asyncify(asyncFn) : asyncFn;
}
function applyEach$1(eachfn) {
return function(fns/*, ...args*/) {
var args = slice(arguments, 1);
var go = initialParams(function(args, callback) {
var that = this;
return eachfn(fns, function (fn, cb) {
wrapAsync(fn).apply(that, args.concat(cb));
}, callback);
});
if (args.length) {
return go.apply(this, args);
}
else {
return go;
}
};
}
/** Detect free variable `global` from Node.js. */
var freeGlobal = typeof global == ‘object‘ && global && global.Object === Object && global;
/** Detect free variable `self`. */
var freeSelf = typeof self == ‘object‘ && self && self.Object === Object && self;
/** Used as a reference to the global object. */
var root = freeGlobal || freeSelf || Function(‘return this‘)();
/** Built-in value references. */
var Symbol$1 = root.Symbol;
/** Used for built-in method references. */
var objectProto = Object.prototype;
/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;
/**
* Used to resolve the
* [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
* of values.
*/
var nativeObjectToString = objectProto.toString;
/** Built-in value references. */
var symToStringTag$1 = Symbol$1 ? Symbol$1.toStringTag : undefined;
/**
* A specialized version of `baseGetTag` which ignores `Symbol.toStringTag` values.
*
* @private
* @param {*} value The value to query.
* @returns {string} Returns the raw `toStringTag`.
*/
function getRawTag(value) {
var isOwn = hasOwnProperty.call(value, symToStringTag$1),
tag = value[symToStringTag$1];
try {
value[symToStringTag$1] = undefined;
var unmasked = true;
} catch (e) {}
var result = nativeObjectToString.call(value);
if (unmasked) {
if (isOwn) {
value[symToStringTag$1] = tag;
} else {
delete value[symToStringTag$1];
}
}
return result;
}
/** Used for built-in method references. */
var objectProto$1 = Object.prototype;
/**
* Used to resolve the
* [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
* of values.
*/
var nativeObjectToString$1 = objectProto$1.toString;
/**
* Converts `value` to a string using `Object.prototype.toString`.
*
* @private
* @param {*} value The value to convert.
* @returns {string} Returns the converted string.
*/
function objectToString(value) {
return nativeObjectToString$1.call(value);
}
/** `Object#toString` result references. */
var nullTag = ‘[object Null]‘;
var undefinedTag = ‘[object Undefined]‘;
/** Built-in value references. */
var symToStringTag = Symbol$1 ? Symbol$1.toStringTag : undefined;
/**
* The base implementation of `getTag` without fallbacks for buggy environments.
*
* @private
* @param {*} value The value to query.
* @returns {string} Returns the `toStringTag`.
*/
function baseGetTag(value) {
if (value == null) {
return value === undefined ? undefinedTag : nullTag;
}
value = Object(value);
return (symToStringTag && symToStringTag in value)
? getRawTag(value)
: objectToString(value);
}
/** `Object#toString` result references. */
var asyncTag = ‘[object AsyncFunction]‘;
var funcTag = ‘[object Function]‘;
var genTag = ‘[object GeneratorFunction]‘;
var proxyTag = ‘[object Proxy]‘;
/**
* Checks if `value` is classified as a `Function` object.
*
* @static
* @memberOf _
* @since 0.1.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a function, else `false`.
* @example
*
* _.isFunction(_);
* // => true
*
* _.isFunction(/abc/);
* // => false
*/
function isFunction(value) {
if (!isObject(value)) {
return false;
}
// The use of `Object#toString` avoids issues with the `typeof` operator
// in Safari 9 which returns ‘object‘ for typed arrays and other constructors.
var tag = baseGetTag(value);
return tag == funcTag || tag == genTag || tag == asyncTag || tag == proxyTag;
}
/** Used as references for various `Number` constants. */
var MAX_SAFE_INTEGER = 9007199254740991;
/**
* Checks if `value` is a valid array-like length.
*
* **Note:** This method is loosely based on
* [`ToLength`](http://ecma-international.org/ecma-262/7.0/#sec-tolength).
*
* @static
* @memberOf _
* @since 4.0.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a valid length, else `false`.
* @example
*
* _.isLength(3);
* // => true
*
* _.isLength(Number.MIN_VALUE);
* // => false
*
* _.isLength(Infinity);
* // => false
*
* _.isLength(‘3‘);
* // => false
*/
function isLength(value) {
return typeof value == ‘number‘ &&
value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
}
/**
* Checks if `value` is array-like. A value is considered array-like if it‘s
* not a function and has a `value.length` that‘s an integer greater than or
* equal to `0` and less than or equal to `Number.MAX_SAFE_INTEGER`.
*
* @static
* @memberOf _
* @since 4.0.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is array-like, else `false`.
* @example
*
* _.isArrayLike([1, 2, 3]);
* // => true
*
* _.isArrayLike(document.body.children);
* // => true
*
* _.isArrayLike(‘abc‘);
* // => true
*
* _.isArrayLike(_.noop);
* // => false
*/
function isArrayLike(value) {
return value != null && isLength(value.length) && !isFunction(value);
}
// A temporary value used to identify if the loop should be broken.
// See #1064, #1293
var breakLoop = {};
/**
* This method returns `undefined`.
*
* @static
* @memberOf _
* @since 2.3.0
* @category Util
* @example
*
* _.times(2, _.noop);
* // => [undefined, undefined]
*/
// 空函数
function noop() {
// No operation performed.
}
// 一次(偏函数)
function once(fn) { // fn: waterfall的第二个参数(回调函数)
return function () {
if (fn === null) return;
var callFn = fn;
fn = null; // 把上级函数作用域中的fn置空
callFn.apply(this, arguments); // 调用回调函数
};
}
var iteratorSymbol = typeof Symbol === ‘function‘ && Symbol.iterator;
var getIterator = function (coll) {
return iteratorSymbol && coll[iteratorSymbol] && coll[iteratorSymbol]();
};
/**
* The base implementation of `_.times` without support for iteratee shorthands
* or max array length checks.
*
* @private
* @param {number} n The number of times to invoke `iteratee`.
* @param {Function} iteratee The function invoked per iteration.
* @returns {Array} Returns the array of results.
*/
function baseTimes(n, iteratee) {
var index = -1,
result = Array(n);
while (++index < n) {
result[index] = iteratee(index);
}
return result;
}
/**
* Checks if `value` is object-like. A value is object-like if it‘s not `null`
* and has a `typeof` result of "object".
*
* @static
* @memberOf _
* @since 4.0.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is object-like, else `false`.
* @example
*
* _.isObjectLike({});
* // => true
*
* _.isObjectLike([1, 2, 3]);
* // => true
*
* _.isObjectLike(_.noop);
* // => false
*
* _.isObjectLike(null);
* // => false
*/
function isObjectLike(value) {
return value != null && typeof value == ‘object‘;
}
/** `Object#toString` result references. */
var argsTag = ‘[object Arguments]‘;
/**
* The base implementation of `_.isArguments`.
*
* @private
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is an `arguments` object,
*/
function baseIsArguments(value) {
return isObjectLike(value) && baseGetTag(value) == argsTag;
}
/** Used for built-in method references. */
var objectProto$3 = Object.prototype;
/** Used to check objects for own properties. */
var hasOwnProperty$2 = objectProto$3.hasOwnProperty;
/** Built-in value references. */
var propertyIsEnumerable = objectProto$3.propertyIsEnumerable;
/**
* Checks if `value` is likely an `arguments` object.
*
* @static
* @memberOf _
* @since 0.1.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is an `arguments` object,
* else `false`.
* @example
*
* _.isArguments(function() { return arguments; }());
* // => true
*
* _.isArguments([1, 2, 3]);
* // => false
*/
var isArguments = baseIsArguments(function() { return arguments; }()) ? baseIsArguments : function(value) {
return isObjectLike(value) && hasOwnProperty$2.call(value, ‘callee‘) &&
!propertyIsEnumerable.call(value, ‘callee‘);
};
/**
* Checks if `value` is classified as an `Array` object.
*
* @static
* @memberOf _
* @since 0.1.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is an array, else `false`.
* @example
*
* _.isArray([1, 2, 3]);
* // => true
*
* _.isArray(document.body.children);
* // => false
*
* _.isArray(‘abc‘);
* // => false
*
* _.isArray(_.noop);
* // => false
*/
var isArray = Array.isArray; // 把数组的isArray赋给isArray变量
/**
* This method returns `false`.
*
* @static
* @memberOf _
* @since 4.13.0
* @category Util
* @returns {boolean} Returns `false`.
* @example
*
* _.times(2, _.stubFalse);
* // => [false, false]
*/
function stubFalse() {
return false;
}
/** Detect free variable `exports`. */
var freeExports = typeof exports == ‘object‘ && exports && !exports.nodeType && exports;
/** Detect free variable `module`. */
var freeModule = freeExports && typeof module == ‘object‘ && module && !module.nodeType && module;
/** Detect the popular CommonJS extension `module.exports`. */
var moduleExports = freeModule && freeModule.exports === freeExports;
/** Built-in value references. */
var Buffer = moduleExports ? root.Buffer : undefined;
/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeIsBuffer = Buffer ? Buffer.isBuffer : undefined;
/**
* Checks if `value` is a buffer.
*
* @static
* @memberOf _
* @since 4.3.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a buffer, else `false`.
* @example
*
* _.isBuffer(new Buffer(2));
* // => true
*
* _.isBuffer(new Uint8Array(2));
* // => false
*/
var isBuffer = nativeIsBuffer || stubFalse;
/** Used as references for various `Number` constants. */
var MAX_SAFE_INTEGER$1 = 9007199254740991;
/** Used to detect unsigned integer values. */
var reIsUint = /^(?:0|[1-9]\d*)$/;
/**
* Checks if `value` is a valid array-like index.
*
* @private
* @param {*} value The value to check.
* @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
* @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
*/
function isIndex(value, length) {
length = length == null ? MAX_SAFE_INTEGER$1 : length;
return !!length &&
(typeof value == ‘number‘ || reIsUint.test(value)) &&
(value > -1 && value % 1 == 0 && value < length);
}
/** `Object#toString` result references. */
var argsTag$1 = ‘[object Arguments]‘;
var arrayTag = ‘[object Array]‘;
var boolTag = ‘[object Boolean]‘;
var dateTag = ‘[object Date]‘;
var errorTag = ‘[object Error]‘;
var funcTag$1 = ‘[object Function]‘;
var mapTag = ‘[object Map]‘;
var numberTag = ‘[object Number]‘;
var objectTag = ‘[object Object]‘;
var regexpTag = ‘[object RegExp]‘;
var setTag = ‘[object Set]‘;
var stringTag = ‘[object String]‘;
var weakMapTag = ‘[object WeakMap]‘;
var arrayBufferTag = ‘[object ArrayBuffer]‘;
var dataViewTag = ‘[object DataView]‘;
var float32Tag = ‘[object Float32Array]‘;
var float64Tag = ‘[object Float64Array]‘;
var int8Tag = ‘[object Int8Array]‘;
var int16Tag = ‘[object Int16Array]‘;
var int32Tag = ‘[object Int32Array]‘;
var uint8Tag = ‘[object Uint8Array]‘;
var uint8ClampedTag = ‘[object Uint8ClampedArray]‘;
var uint16Tag = ‘[object Uint16Array]‘;
var uint32Tag = ‘[object Uint32Array]‘;
/** Used to identify `toStringTag` values of typed arrays. */
var typedArrayTags = {};
typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
typedArrayTags[uint32Tag] = true;
typedArrayTags[argsTag$1] = typedArrayTags[arrayTag] =
typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
typedArrayTags[dataViewTag] = typedArrayTags[dateTag] =
typedArrayTags[errorTag] = typedArrayTags[funcTag$1] =
typedArrayTags[mapTag] = typedArrayTags[numberTag] =
typedArrayTags[objectTag] = typedArrayTags[regexpTag] =
typedArrayTags[setTag] = typedArrayTags[stringTag] =
typedArrayTags[weakMapTag] = false;
/**
* The base implementation of `_.isTypedArray` without Node.js optimizations.
*
* @private
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a typed array, else `false`.
*/
function baseIsTypedArray(value) {
return isObjectLike(value) &&
isLength(value.length) && !!typedArrayTags[baseGetTag(value)];
}
/**
* The base implementation of `_.unary` without support for storing metadata.
*
* @private
* @param {Function} func The function to cap arguments for.
* @returns {Function} Returns the new capped function.
*/
function baseUnary(func) {
return function(value) {
return func(value);
};
}
/** Detect free variable `exports`. */
var freeExports$1 = typeof exports == ‘object‘ && exports && !exports.nodeType && exports;
/** Detect free variable `module`. */
var freeModule$1 = freeExports$1 && typeof module == ‘object‘ && module && !module.nodeType && module;
/** Detect the popular CommonJS extension `module.exports`. */
var moduleExports$1 = freeModule$1 && freeModule$1.exports === freeExports$1;
/** Detect free variable `process` from Node.js. */
var freeProcess = moduleExports$1 && freeGlobal.process;
/** Used to access faster Node.js helpers. */
var nodeUtil = (function() {
try {
return freeProcess && freeProcess.binding(‘util‘);
} catch (e) {}
}());
/* Node.js helper references. */
var nodeIsTypedArray = nodeUtil && nodeUtil.isTypedArray;
/**
* Checks if `value` is classified as a typed array.
*
* @static
* @memberOf _
* @since 3.0.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a typed array, else `false`.
* @example
*
* _.isTypedArray(new Uint8Array);
* // => true
*
* _.isTypedArray([]);
* // => false
*/
var isTypedArray = nodeIsTypedArray ? baseUnary(nodeIsTypedArray) : baseIsTypedArray;
/** Used for built-in method references. */
var objectProto$2 = Object.prototype;
/** Used to check objects for own properties. */
var hasOwnProperty$1 = objectProto$2.hasOwnProperty;
/**
* Creates an array of the enumerable property names of the array-like `value`.
*
* @private
* @param {*} value The value to query.
* @param {boolean} inherited Specify returning inherited property names.
* @returns {Array} Returns the array of property names.
*/
function arrayLikeKeys(value, inherited) {
var isArr = isArray(value),
isArg = !isArr && isArguments(value),
isBuff = !isArr && !isArg && isBuffer(value),
isType = !isArr && !isArg && !isBuff && isTypedArray(value),
skipIndexes = isArr || isArg || isBuff || isType,
result = skipIndexes ? baseTimes(value.length, String) : [],
length = result.length;
for (var key in value) {
if ((inherited || hasOwnProperty$1.call(value, key)) &&
!(skipIndexes && (
// Safari 9 has enumerable `arguments.length` in strict mode.
key == ‘length‘ ||
// Node.js 0.10 has enumerable non-index properties on buffers.
(isBuff && (key == ‘offset‘ || key == ‘parent‘)) ||
// PhantomJS 2 has enumerable non-index properties on typed arrays.
(isType && (key == ‘buffer‘ || key == ‘byteLength‘ || key == ‘byteOffset‘)) ||
// Skip index properties.
isIndex(key, length)
))) {
result.push(key);
}
}
return result;
}
/** Used for built-in method references. */
var objectProto$5 = Object.prototype;
/**
* Checks if `value` is likely a prototype object.
*
* @private
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a prototype, else `false`.
*/
function isPrototype(value) {
var Ctor = value && value.constructor,
proto = (typeof Ctor == ‘function‘ && Ctor.prototype) || objectProto$5;
return value === proto;
}
/**
* Creates a unary function that invokes `func` with its argument transformed.
*
* @private
* @param {Function} func The function to wrap.
* @param {Function} transform The argument transform.
* @returns {Function} Returns the new function.
*/
function overArg(func, transform) {
return function(arg) {
return func(transform(arg));
};
}
/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeKeys = overArg(Object.keys, Object);
/** Used for built-in method references. */
var objectProto$4 = Object.prototype;
/** Used to check objects for own properties. */
var hasOwnProperty$3 = objectProto$4.hasOwnProperty;
/**
* The base implementation of `_.keys` which doesn‘t treat sparse arrays as dense.
*
* @private
* @param {Object} object The object to query.
* @returns {Array} Returns the array of property names.
*/
function baseKeys(object) {
if (!isPrototype(object)) {
return nativeKeys(object);
}
var result = [];
for (var key in Object(object)) {
if (hasOwnProperty$3.call(object, key) && key != ‘constructor‘) {
result.push(key);
}
}
return result;
}
/**
* Creates an array of the own enumerable property names of `object`.
*
* **Note:** Non-object values are coerced to objects. See the
* [ES spec](http://ecma-international.org/ecma-262/7.0/#sec-object.keys)
* for more details.
*
* @static
* @since 0.1.0
* @memberOf _
* @category Object
* @param {Object} object The object to query.
* @returns {Array} Returns the array of property names.
* @example
*
* function Foo() {
* this.a = 1;
* this.b = 2;
* }
*
* Foo.prototype.c = 3;
*
* _.keys(new Foo);
* // => [‘a‘, ‘b‘] (iteration order is not guaranteed)
*
* _.keys(‘hi‘);
* // => [‘0‘, ‘1‘]
*/
function keys(object) {
return isArrayLike(object) ? arrayLikeKeys(object) : baseKeys(object);
}
function createArrayIterator(coll) {
var i = -1;
var len = coll.length;
return function next() {
return ++i < len ? {value: coll[i], key: i} : null;
}
}
function createES2015Iterator(iterator) {
var i = -1;
return function next() {
var item = iterator.next();
if (item.done)
return null;
i++;
return {value: item.value, key: i};
}
}
function createObjectIterator(obj) {
var okeys = keys(obj);
var i = -1;
var len = okeys.length;
return function next() {
var key = okeys[++i];
return i < len ? {value: obj[key], key: key} : null;
};
}
function iterator(coll) {
if (isArrayLike(coll)) {
return createArrayIterator(coll);
}
var iterator = getIterator(coll);
return iterator ? createES2015Iterator(iterator) : createObjectIterator(coll);
}
// 执行一次
function onlyOnce(fn) {
return function() {
if (fn === null) throw new Error("Callback was already called."); // 回调已被调用
var callFn = fn;
fn = null;
callFn.apply(this, arguments); //调用callFn 参数就是用户回调函数中的参数
};
};
function _eachOfLimit(limit) {
return function (obj, iteratee, callback) {
callback = once(callback || noop);
if (limit <= 0 || !obj) {
return callback(null);
}
var nextElem = iterator(obj);
var done = false;
var running = 0;
function iterateeCallback(err, value) {
running -= 1;
if (err) {
done = true;
callback(err);
}
else if (value === breakLoop || (done && running <= 0)) {
done = true;
return callback(null);
}
else {
replenish();
}
}
function replenish () {
while (running < limit && !done) {
var elem = nextElem();
if (elem === null) {
done = true;
if (running <= 0) {
callback(null);
}
return;
}
running += 1;
iteratee(elem.value, elem.key, onlyOnce(iterateeCallback));
}
}
replenish();
};
}
/**
* The same as [`eachOf`]{@link module:Collections.eachOf} but runs a maximum of `limit` async operations at a
* time.
*
* @name eachOfLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.eachOf]{@link module:Collections.eachOf}
* @alias forEachOfLimit
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - An async function to apply to each
* item in `coll`. The `key` is the item‘s key, or index in the case of an
* array.
* Invoked with (item, key, callback).
* @param {Function} [callback] - A callback which is called when all
* `iteratee` functions have finished, or an error occurs. Invoked with (err).
*/
function eachOfLimit(coll, limit, iteratee, callback) {
_eachOfLimit(limit)(coll, wrapAsync(iteratee), callback);
}
function doLimit(fn, limit) {
return function (iterable, iteratee, callback) {
return fn(iterable, limit, iteratee, callback);
};
}
// eachOf implementation optimized for array-likes
function eachOfArrayLike(coll, iteratee, callback) {
callback = once(callback || noop);
var index = 0,
completed = 0,
length = coll.length;
if (length === 0) {
callback(null);
}
function iteratorCallback(err, value) {
if (err) {
callback(err);
} else if ((++completed === length) || value === breakLoop) {
callback(null);
}
}
for (; index < length; index++) {
iteratee(coll[index], index, onlyOnce(iteratorCallback));
}
}
// a generic version of eachOf which can handle array, object, and iterator cases.
var eachOfGeneric = doLimit(eachOfLimit, Infinity);
/**
* Like [`each`]{@link module:Collections.each}, except that it passes the key (or index) as the second argument
* to the iteratee.
*
* @name eachOf
* @static
* @memberOf module:Collections
* @method
* @alias forEachOf
* @category Collection
* @see [async.each]{@link module:Collections.each}
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - A function to apply to each
* item in `coll`.
* The `key` is the item‘s key, or index in the case of an array.
* Invoked with (item, key, callback).
* @param {Function} [callback] - A callback which is called when all
* `iteratee` functions have finished, or an error occurs. Invoked with (err).
* @example
*
* var obj = {dev: "/dev.json", test: "/test.json", prod: "/prod.json"};
* var configs = {};
*
* async.forEachOf(obj, function (value, key, callback) {
* fs.readFile(__dirname + value, "utf8", function (err, data) {
* if (err) return callback(err);
* try {
* configs[key] = JSON.parse(data);
* } catch (e) {
* return callback(e);
* }
* callback();
* });
* }, function (err) {
* if (err) console.error(err.message);
* // configs is now a map of JSON data
* doSomethingWith(configs);
* });
*/
var eachOf = function(coll, iteratee, callback) {
var eachOfImplementation = isArrayLike(coll) ? eachOfArrayLike : eachOfGeneric;
eachOfImplementation(coll, wrapAsync(iteratee), callback);
};
function doParallel(fn) {
return function (obj, iteratee, callback) {
return fn(eachOf, obj, wrapAsync(iteratee), callback);
};
}
function _asyncMap(eachfn, arr, iteratee, callback) {
callback = callback || noop;
arr = arr || [];
var results = [];
var counter = 0;
var _iteratee = wrapAsync(iteratee);
eachfn(arr, function (value, _, callback) {
var index = counter++;
_iteratee(value, function (err, v) {
results[index] = v;
callback(err);
});
}, function (err) {
callback(err, results);
});
}
/**
* Produces a new collection of values by mapping each value in `coll` through
* the `iteratee` function. The `iteratee` is called with an item from `coll`
* and a callback for when it has finished processing. Each of these callback
* takes 2 arguments: an `error`, and the transformed item from `coll`. If
* `iteratee` passes an error to its callback, the main `callback` (for the
* `map` function) is immediately called with the error.
*
* Note, that since this function applies the `iteratee` to each item in
* parallel, there is no guarantee that the `iteratee` functions will complete
* in order. However, the results array will be in the same order as the
* original `coll`.
*
* If `map` is passed an Object, the results will be an Array. The results
* will roughly be in the order of the original Objects‘ keys (but this can
* vary across JavaScript engines).
*
* @name map
* @static
* @memberOf module:Collections
* @method
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* The iteratee should complete with the transformed item.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. Results is an Array of the
* transformed items from the `coll`. Invoked with (err, results).
* @example
*
* async.map([‘file1‘,‘file2‘,‘file3‘], fs.stat, function(err, results) {
* // results is now an array of stats for each file
* });
*/
var map = doParallel(_asyncMap);
/**
* Applies the provided arguments to each function in the array, calling
* `callback` after all functions have completed. If you only provide the first
* argument, `fns`, then it will return a function which lets you pass in the
* arguments as if it were a single function call. If more arguments are
* provided, `callback` is required while `args` is still optional.
*
* @name applyEach
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Array|Iterable|Object} fns - A collection of {@link AsyncFunction}s
* to all call with the same arguments
* @param {...*} [args] - any number of separate arguments to pass to the
* function.
* @param {Function} [callback] - the final argument should be the callback,
* called when all functions have completed processing.
* @returns {Function} - If only the first argument, `fns`, is provided, it will
* return a function which lets you pass in the arguments as if it were a single
* function call. The signature is `(..args, callback)`. If invoked with any
* arguments, `callback` is required.
* @example
*
* async.applyEach([enableSearch, updateSchema], ‘bucket‘, callback);
*
* // partial application example:
* async.each(
* buckets,
* async.applyEach([enableSearch, updateSchema]),
* callback
* );
*/
var applyEach = applyEach$1(map);
function doParallelLimit(fn) {
return function (obj, limit, iteratee, callback) {
return fn(_eachOfLimit(limit), obj, wrapAsync(iteratee), callback);
};
}
/**
* The same as [`map`]{@link module:Collections.map} but runs a maximum of `limit` async operations at a time.
*
* @name mapLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.map]{@link module:Collections.map}
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* The iteratee should complete with the transformed item.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. Results is an array of the
* transformed items from the `coll`. Invoked with (err, results).
*/
var mapLimit = doParallelLimit(_asyncMap);
/**
* The same as [`map`]{@link module:Collections.map} but runs only a single async operation at a time.
*
* @name mapSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.map]{@link module:Collections.map}
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* The iteratee should complete with the transformed item.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. Results is an array of the
* transformed items from the `coll`. Invoked with (err, results).
*/
var mapSeries = doLimit(mapLimit, 1);
/**
* The same as [`applyEach`]{@link module:ControlFlow.applyEach} but runs only a single async operation at a time.
*
* @name applyEachSeries
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.applyEach]{@link module:ControlFlow.applyEach}
* @category Control Flow
* @param {Array|Iterable|Object} fns - A collection of {@link AsyncFunction}s to all
* call with the same arguments
* @param {...*} [args] - any number of separate arguments to pass to the
* function.
* @param {Function} [callback] - the final argument should be the callback,
* called when all functions have completed processing.
* @returns {Function} - If only the first argument is provided, it will return
* a function which lets you pass in the arguments as if it were a single
* function call.
*/
var applyEachSeries = applyEach$1(mapSeries);
/**
* Creates a continuation function with some arguments already applied.
*
* Useful as a shorthand when combined with other control flow functions. Any
* arguments passed to the returned function are added to the arguments
* originally passed to apply.
*
* @name apply
* @static
* @memberOf module:Utils
* @method
* @category Util
* @param {Function} fn - The function you want to eventually apply all
* arguments to. Invokes with (arguments...).
* @param {...*} arguments... - Any number of arguments to automatically apply
* when the continuation is called.
* @returns {Function} the partially-applied function
* @example
*
* // using apply
* async.parallel([
* async.apply(fs.writeFile, ‘testfile1‘, ‘test1‘),
* async.apply(fs.writeFile, ‘testfile2‘, ‘test2‘)
* ]);
*
*
* // the same process without using apply
* async.parallel([
* function(callback) {
* fs.writeFile(‘testfile1‘, ‘test1‘, callback);
* },
* function(callback) {
* fs.writeFile(‘testfile2‘, ‘test2‘, callback);
* }
* ]);
*
* // It‘s possible to pass any number of additional arguments when calling the
* // continuation:
*
* node> var fn = async.apply(sys.puts, ‘one‘);
* node> fn(‘two‘, ‘three‘);
* one
* two
* three
*/
var apply = function(fn/*, ...args*/) {
var args = slice(arguments, 1);
return function(/*callArgs*/) {
var callArgs = slice(arguments);
return fn.apply(null, args.concat(callArgs));
};
};
/**
* A specialized version of `_.forEach` for arrays without support for
* iteratee shorthands.
*
* @private
* @param {Array} [array] The array to iterate over.
* @param {Function} iteratee The function invoked per iteration.
* @returns {Array} Returns `array`.
*/
function arrayEach(array, iteratee) {
var index = -1,
length = array == null ? 0 : array.length;
while (++index < length) {
if (iteratee(array[index], index, array) === false) {
break;
}
}
return array;
}
/**
* Creates a base function for methods like `_.forIn` and `_.forOwn`.
*
* @private
* @param {boolean} [fromRight] Specify iterating from right to left.
* @returns {Function} Returns the new base function.
*/
function createBaseFor(fromRight) {
return function(object, iteratee, keysFunc) {
var index = -1,
iterable = Object(object),
props = keysFunc(object),
length = props.length;
while (length--) {
var key = props[fromRight ? length : ++index];
if (iteratee(iterable[key], key, iterable) === false) {
break;
}
}
return object;
};
}
/**
* The base implementation of `baseForOwn` which iterates over `object`
* properties returned by `keysFunc` and invokes `iteratee` for each property.
* Iteratee functions may exit iteration early by explicitly returning `false`.
*
* @private
* @param {Object} object The object to iterate over.
* @param {Function} iteratee The function invoked per iteration.
* @param {Function} keysFunc The function to get the keys of `object`.
* @returns {Object} Returns `object`.
*/
var baseFor = createBaseFor();
/**
* The base implementation of `_.forOwn` without support for iteratee shorthands.
*
* @private
* @param {Object} object The object to iterate over.
* @param {Function} iteratee The function invoked per iteration.
* @returns {Object} Returns `object`.
*/
function baseForOwn(object, iteratee) {
return object && baseFor(object, iteratee, keys);
}
/**
* The base implementation of `_.findIndex` and `_.findLastIndex` without
* support for iteratee shorthands.
*
* @private
* @param {Array} array The array to inspect.
* @param {Function} predicate The function invoked per iteration.
* @param {number} fromIndex The index to search from.
* @param {boolean} [fromRight] Specify iterating from right to left.
* @returns {number} Returns the index of the matched value, else `-1`.
*/
function baseFindIndex(array, predicate, fromIndex, fromRight) {
var length = array.length,
index = fromIndex + (fromRight ? 1 : -1);
while ((fromRight ? index-- : ++index < length)) {
if (predicate(array[index], index, array)) {
return index;
}
}
return -1;
}
/**
* The base implementation of `_.isNaN` without support for number objects.
*
* @private
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
*/
function baseIsNaN(value) {
return value !== value;
}
/**
* A specialized version of `_.indexOf` which performs strict equality
* comparisons of values, i.e. `===`.
*
* @private
* @param {Array} array The array to inspect.
* @param {*} value The value to search for.
* @param {number} fromIndex The index to search from.
* @returns {number} Returns the index of the matched value, else `-1`.
*/
function strictIndexOf(array, value, fromIndex) {
var index = fromIndex - 1,
length = array.length;
while (++index < length) {
if (array[index] === value) {
return index;
}
}
return -1;
}
/**
* The base implementation of `_.indexOf` without `fromIndex` bounds checks.
*
* @private
* @param {Array} array The array to inspect.
* @param {*} value The value to search for.
* @param {number} fromIndex The index to search from.
* @returns {number} Returns the index of the matched value, else `-1`.
*/
function baseIndexOf(array, value, fromIndex) {
return value === value
? strictIndexOf(array, value, fromIndex)
: baseFindIndex(array, baseIsNaN, fromIndex);
}
/**
* Determines the best order for running the {@link AsyncFunction}s in `tasks`, based on
* their requirements. Each function can optionally depend on other functions
* being completed first, and each function is run as soon as its requirements
* are satisfied.
*
* If any of the {@link AsyncFunction}s pass an error to their callback, the `auto` sequence
* will stop. Further tasks will not execute (so any other functions depending
* on it will not run), and the main `callback` is immediately called with the
* error.
*
* {@link AsyncFunction}s also receive an object containing the results of functions which
* have completed so far as the first argument, if they have dependencies. If a
* task function has no dependencies, it will only be passed a callback.
*
* @name auto
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Object} tasks - An object. Each of its properties is either a
* function or an array of requirements, with the {@link AsyncFunction} itself the last item
* in the array. The object‘s key of a property serves as the name of the task
* defined by that property, i.e. can be used when specifying requirements for
* other tasks. The function receives one or two arguments:
* * a `results` object, containing the results of the previously executed
* functions, only passed if the task has any dependencies,
* * a `callback(err, result)` function, which must be called when finished,
* passing an `error` (which can be `null`) and the result of the function‘s
* execution.
* @param {number} [concurrency=Infinity] - An optional `integer` for
* determining the maximum number of tasks that can be run in parallel. By
* default, as many as possible.
* @param {Function} [callback] - An optional callback which is called when all
* the tasks have been completed. It receives the `err` argument if any `tasks`
* pass an error to their callback. Results are always returned; however, if an
* error occurs, no further `tasks` will be performed, and the results object
* will only contain partial results. Invoked with (err, results).
* @returns undefined
* @example
*
* async.auto({
* // this function will just be passed a callback
* readData: async.apply(fs.readFile, ‘data.txt‘, ‘utf-8‘),
* showData: [‘readData‘, function(results, cb) {
* // results.readData is the file‘s contents
* // ...
* }]
* }, callback);
*
* async.auto({
* get_data: function(callback) {
* console.log(‘in get_data‘);
* // async code to get some data
* callback(null, ‘data‘, ‘converted to array‘);
* },
* make_folder: function(callback) {
* console.log(‘in make_folder‘);
* // async code to create a directory to store a file in
* // this is run at the same time as getting the data
* callback(null, ‘folder‘);
* },
* write_file: [‘get_data‘, ‘make_folder‘, function(results, callback) {
* console.log(‘in write_file‘, JSON.stringify(results));
* // once there is some data and the directory exists,
* // write the data to a file in the directory
* callback(null, ‘filename‘);
* }],
* email_link: [‘write_file‘, function(results, callback) {
* console.log(‘in email_link‘, JSON.stringify(results));
* // once the file is written let‘s email a link to it...
* // results.write_file contains the filename returned by write_file.
* callback(null, {‘file‘:results.write_file, ‘email‘:‘[email protected]‘});
* }]
* }, function(err, results) {
* console.log(‘err = ‘, err);
* console.log(‘results = ‘, results);
* });
*/
var auto = function (tasks, concurrency, callback) {
if (typeof concurrency === ‘function‘) {
// concurrency is optional, shift the args.
callback = concurrency;
concurrency = null;
}
callback = once(callback || noop);
var keys$$1 = keys(tasks);
var numTasks = keys$$1.length;
if (!numTasks) {
return callback(null);
}
if (!concurrency) {
concurrency = numTasks;
}
var results = {};
var runningTasks = 0;
var hasError = false;
var listeners = Object.create(null);
var readyTasks = [];
// for cycle detection:
var readyToCheck = []; // tasks that have been identified as reachable
// without the possibility of returning to an ancestor task
var uncheckedDependencies = {};
baseForOwn(tasks, function (task, key) {
if (!isArray(task)) {
// no dependencies
enqueueTask(key, [task]);
readyToCheck.push(key);
return;
}
var dependencies = task.slice(0, task.length - 1);
var remainingDependencies = dependencies.length;
if (remainingDependencies === 0) {
enqueueTask(key, task);
readyToCheck.push(key);
return;
}
uncheckedDependencies[key] = remainingDependencies;
arrayEach(dependencies, function (dependencyName) {
if (!tasks[dependencyName]) {
throw new Error(‘async.auto task `‘ + key +
‘` has a non-existent dependency `‘ +
dependencyName + ‘` in ‘ +
dependencies.join(‘, ‘));
}
addListener(dependencyName, function () {
remainingDependencies--;
if (remainingDependencies === 0) {
enqueueTask(key, task);
}
});
});
});
checkForDeadlocks();
processQueue();
function enqueueTask(key, task) {
readyTasks.push(function () {
runTask(key, task);
});
}
function processQueue() {
if (readyTasks.length === 0 && runningTasks === 0) {
return callback(null, results);
}
while(readyTasks.length && runningTasks < concurrency) {
var run = readyTasks.shift();
run();
}
}
function addListener(taskName, fn) {
var taskListeners = listeners[taskName];
if (!taskListeners) {
taskListeners = listeners[taskName] = [];
}
taskListeners.push(fn);
}
function taskComplete(taskName) {
var taskListeners = listeners[taskName] || [];
arrayEach(taskListeners, function (fn) {
fn();
});
processQueue();
}
function runTask(key, task) {
if (hasError) return;
var taskCallback = onlyOnce(function(err, result) {
runningTasks--;
if (arguments.length > 2) {
result = slice(arguments, 1);
}
if (err) {
var safeResults = {};
baseForOwn(results, function(val, rkey) {
safeResults[rkey] = val;
});
safeResults[key] = result;
hasError = true;
listeners = Object.create(null);
callback(err, safeResults);
} else {
results[key] = result;
taskComplete(key);
}
});
runningTasks++;
var taskFn = wrapAsync(task[task.length - 1]);
if (task.length > 1) {
taskFn(results, taskCallback);
} else {
taskFn(taskCallback);
}
}
function checkForDeadlocks() {
// Kahn‘s algorithm
// https://en.wikipedia.org/wiki/Topological_sorting#Kahn.27s_algorithm
// http://connalle.blogspot.com/2013/10/topological-sortingkahn-algorithm.html
var currentTask;
var counter = 0;
while (readyToCheck.length) {
currentTask = readyToCheck.pop();
counter++;
arrayEach(getDependents(currentTask), function (dependent) {
if (--uncheckedDependencies[dependent] === 0) {
readyToCheck.push(dependent);
}
});
}
if (counter !== numTasks) {
throw new Error(
‘async.auto cannot execute tasks due to a recursive dependency‘
);
}
}
function getDependents(taskName) {
var result = [];
baseForOwn(tasks, function (task, key) {
if (isArray(task) && baseIndexOf(task, taskName, 0) >= 0) {
result.push(key);
}
});
return result;
}
};
/**
* A specialized version of `_.map` for arrays without support for iteratee
* shorthands.
*
* @private
* @param {Array} [array] The array to iterate over.
* @param {Function} iteratee The function invoked per iteration.
* @returns {Array} Returns the new mapped array.
*/
function arrayMap(array, iteratee) {
var index = -1,
length = array == null ? 0 : array.length,
result = Array(length);
while (++index < length) {
result[index] = iteratee(array[index], index, array);
}
return result;
}
/** `Object#toString` result references. */
var symbolTag = ‘[object Symbol]‘;
/**
* Checks if `value` is classified as a `Symbol` primitive or object.
*
* @static
* @memberOf _
* @since 4.0.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
* @example
*
* _.isSymbol(Symbol.iterator);
* // => true
*
* _.isSymbol(‘abc‘);
* // => false
*/
function isSymbol(value) {
return typeof value == ‘symbol‘ ||
(isObjectLike(value) && baseGetTag(value) == symbolTag);
}
/** Used as references for various `Number` constants. */
var INFINITY = 1 / 0;
/** Used to convert symbols to primitives and strings. */
var symbolProto = Symbol$1 ? Symbol$1.prototype : undefined;
var symbolToString = symbolProto ? symbolProto.toString : undefined;
/**
* The base implementation of `_.toString` which doesn‘t convert nullish
* values to empty strings.
*
* @private
* @param {*} value The value to process.
* @returns {string} Returns the string.
*/
function baseToString(value) {
// Exit early for strings to avoid a performance hit in some environments.
if (typeof value == ‘string‘) {
return value;
}
if (isArray(value)) {
// Recursively convert values (susceptible to call stack limits).
return arrayMap(value, baseToString) + ‘‘;
}
if (isSymbol(value)) {
return symbolToString ? symbolToString.call(value) : ‘‘;
}
var result = (value + ‘‘);
return (result == ‘0‘ && (1 / value) == -INFINITY) ? ‘-0‘ : result;
}
/**
* The base implementation of `_.slice` without an iteratee call guard.
*
* @private
* @param {Array} array The array to slice.
* @param {number} [start=0] The start position.
* @param {number} [end=array.length] The end position.
* @returns {Array} Returns the slice of `array`.
*/
function baseSlice(array, start, end) {
var index = -1,
length = array.length;
if (start < 0) {
start = -start > length ? 0 : (length + start);
}
end = end > length ? length : end;
if (end < 0) {
end += length;
}
length = start > end ? 0 : ((end - start) >>> 0);
start >>>= 0;
var result = Array(length);
while (++index < length) {
result[index] = array[index + start];
}
return result;
}
/**
* Casts `array` to a slice if it‘s needed.
*
* @private
* @param {Array} array The array to inspect.
* @param {number} start The start position.
* @param {number} [end=array.length] The end position.
* @returns {Array} Returns the cast slice.
*/
function castSlice(array, start, end) {
var length = array.length;
end = end === undefined ? length : end;
return (!start && end >= length) ? array : baseSlice(array, start, end);
}
/**
* Used by `_.trim` and `_.trimEnd` to get the index of the last string symbol
* that is not found in the character symbols.
*
* @private
* @param {Array} strSymbols The string symbols to inspect.
* @param {Array} chrSymbols The character symbols to find.
* @returns {number} Returns the index of the last unmatched string symbol.
*/
function charsEndIndex(strSymbols, chrSymbols) {
var index = strSymbols.length;
while (index-- && baseIndexOf(chrSymbols, strSymbols[index], 0) > -1) {}
return index;
}
/**
* Used by `_.trim` and `_.trimStart` to get the index of the first string symbol
* that is not found in the character symbols.
*
* @private
* @param {Array} strSymbols The string symbols to inspect.
* @param {Array} chrSymbols The character symbols to find.
* @returns {number} Returns the index of the first unmatched string symbol.
*/
function charsStartIndex(strSymbols, chrSymbols) {
var index = -1,
length = strSymbols.length;
while (++index < length && baseIndexOf(chrSymbols, strSymbols[index], 0) > -1) {}
return index;
}
/**
* Converts an ASCII `string` to an array.
*
* @private
* @param {string} string The string to convert.
* @returns {Array} Returns the converted array.
*/
function asciiToArray(string) {
return string.split(‘‘);
}
/** Used to compose unicode character classes. */
var rsAstralRange = ‘\\ud800-\\udfff‘;
var rsComboMarksRange = ‘\\u0300-\\u036f\\ufe20-\\ufe23‘;
var rsComboSymbolsRange = ‘\\u20d0-\\u20f0‘;
var rsVarRange = ‘\\ufe0e\\ufe0f‘;
/** Used to compose unicode capture groups. */
var rsZWJ = ‘\\u200d‘;
/** Used to detect strings with [zero-width joiners or code points from the astral planes](http://eev.ee/blog/2015/09/12/dark-corners-of-unicode/). */
var reHasUnicode = RegExp(‘[‘ + rsZWJ + rsAstralRange + rsComboMarksRange + rsComboSymbolsRange + rsVarRange + ‘]‘);
/**
* Checks if `string` contains Unicode symbols.
*
* @private
* @param {string} string The string to inspect.
* @returns {boolean} Returns `true` if a symbol is found, else `false`.
*/
function hasUnicode(string) {
return reHasUnicode.test(string);
}
/** Used to compose unicode character classes. */
var rsAstralRange$1 = ‘\\ud800-\\udfff‘;
var rsComboMarksRange$1 = ‘\\u0300-\\u036f\\ufe20-\\ufe23‘;
var rsComboSymbolsRange$1 = ‘\\u20d0-\\u20f0‘;
var rsVarRange$1 = ‘\\ufe0e\\ufe0f‘;
/** Used to compose unicode capture groups. */
var rsAstral = ‘[‘ + rsAstralRange$1 + ‘]‘;
var rsCombo = ‘[‘ + rsComboMarksRange$1 + rsComboSymbolsRange$1 + ‘]‘;
var rsFitz = ‘\\ud83c[\\udffb-\\udfff]‘;
var rsModifier = ‘(?:‘ + rsCombo + ‘|‘ + rsFitz + ‘)‘;
var rsNonAstral = ‘[^‘ + rsAstralRange$1 + ‘]‘;
var rsRegional = ‘(?:\\ud83c[\\udde6-\\uddff]){2}‘;
var rsSurrPair = ‘[\\ud800-\\udbff][\\udc00-\\udfff]‘;
var rsZWJ$1 = ‘\\u200d‘;
/** Used to compose unicode regexes. */
var reOptMod = rsModifier + ‘?‘;
var rsOptVar = ‘[‘ + rsVarRange$1 + ‘]?‘;
var rsOptJoin = ‘(?:‘ + rsZWJ$1 + ‘(?:‘ + [rsNonAstral, rsRegional, rsSurrPair].join(‘|‘) + ‘)‘ + rsOptVar + reOptMod + ‘)*‘;
var rsSeq = rsOptVar + reOptMod + rsOptJoin;
var rsSymbol = ‘(?:‘ + [rsNonAstral + rsCombo + ‘?‘, rsCombo, rsRegional, rsSurrPair, rsAstral].join(‘|‘) + ‘)‘;
/** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
var reUnicode = RegExp(rsFitz + ‘(?=‘ + rsFitz + ‘)|‘ + rsSymbol + rsSeq, ‘g‘);
/**
* Converts a Unicode `string` to an array.
*
* @private
* @param {string} string The string to convert.
* @returns {Array} Returns the converted array.
*/
function unicodeToArray(string) {
return string.match(reUnicode) || [];
}
/**
* Converts `string` to an array.
*
* @private
* @param {string} string The string to convert.
* @returns {Array} Returns the converted array.
*/
function stringToArray(string) {
return hasUnicode(string)
? unicodeToArray(string)
: asciiToArray(string);
}
/**
* Converts `value` to a string. An empty string is returned for `null`
* and `undefined` values. The sign of `-0` is preserved.
*
* @static
* @memberOf _
* @since 4.0.0
* @category Lang
* @param {*} value The value to convert.
* @returns {string} Returns the converted string.
* @example
*
* _.toString(null);
* // => ‘‘
*
* _.toString(-0);
* // => ‘-0‘
*
* _.toString([1, 2, 3]);
* // => ‘1,2,3‘
*/
function toString(value) {
return value == null ? ‘‘ : baseToString(value);
}
/** Used to match leading and trailing whitespace. */
var reTrim = /^\s+|\s+$/g;
/**
* Removes leading and trailing whitespace or specified characters from `string`.
*
* @static
* @memberOf _
* @since 3.0.0
* @category String
* @param {string} [string=‘‘] The string to trim.
* @param {string} [chars=whitespace] The characters to trim.
* @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.
* @returns {string} Returns the trimmed string.
* @example
*
* _.trim(‘ abc ‘);
* // => ‘abc‘
*
* _.trim(‘-_-abc-_-‘, ‘_-‘);
* // => ‘abc‘
*
* _.map([‘ foo ‘, ‘ bar ‘], _.trim);
* // => [‘foo‘, ‘bar‘]
*/
function trim(string, chars, guard) {
string = toString(string);
if (string && (guard || chars === undefined)) {
return string.replace(reTrim, ‘‘);
}
if (!string || !(chars = baseToString(chars))) {
return string;
}
var strSymbols = stringToArray(string),
chrSymbols = stringToArray(chars),
start = charsStartIndex(strSymbols, chrSymbols),
end = charsEndIndex(strSymbols, chrSymbols) + 1;
return castSlice(strSymbols, start, end).join(‘‘);
}
var FN_ARGS = /^(?:async\s+)?(function)?\s*[^\(]*\(\s*([^\)]*)\)/m;
var FN_ARG_SPLIT = /,/;
var FN_ARG = /(=.+)?(\s*)$/;
var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
function parseParams(func) {
func = func.toString().replace(STRIP_COMMENTS, ‘‘);
func = func.match(FN_ARGS)[2].replace(‘ ‘, ‘‘);
func = func ? func.split(FN_ARG_SPLIT) : [];
func = func.map(function (arg){
return trim(arg.replace(FN_ARG, ‘‘));
});
return func;
}
/**
* A dependency-injected version of the [async.auto]{@link module:ControlFlow.auto} function. Dependent
* tasks are specified as parameters to the function, after the usual callback
* parameter, with the parameter names matching the names of the tasks it
* depends on. This can provide even more readable task graphs which can be
* easier to maintain.
*
* If a final callback is specified, the task results are similarly injected,
* specified as named parameters after the initial error parameter.
*
* The autoInject function is purely syntactic sugar and its semantics are
* otherwise equivalent to [async.auto]{@link module:ControlFlow.auto}.
*
* @name autoInject
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.auto]{@link module:ControlFlow.auto}
* @category Control Flow
* @param {Object} tasks - An object, each of whose properties is an {@link AsyncFunction} of
* the form ‘func([dependencies...], callback). The object‘s key of a property
* serves as the name of the task defined by that property, i.e. can be used
* when specifying requirements for other tasks.
* * The `callback` parameter is a `callback(err, result)` which must be called
* when finished, passing an `error` (which can be `null`) and the result of
* the function‘s execution. The remaining parameters name other tasks on
* which the task is dependent, and the results from those tasks are the
* arguments of those parameters.
* @param {Function} [callback] - An optional callback which is called when all
* the tasks have been completed. It receives the `err` argument if any `tasks`
* pass an error to their callback, and a `results` object with any completed
* task results, similar to `auto`.
* @example
*
* // The example from `auto` can be rewritten as follows:
* async.autoInject({
* get_data: function(callback) {
* // async code to get some data
* callback(null, ‘data‘, ‘converted to array‘);
* },
* make_folder: function(callback) {
* // async code to create a directory to store a file in
* // this is run at the same time as getting the data
* callback(null, ‘folder‘);
* },
* write_file: function(get_data, make_folder, callback) {
* // once there is some data and the directory exists,
* // write the data to a file in the directory
* callback(null, ‘filename‘);
* },
* email_link: function(write_file, callback) {
* // once the file is written let‘s email a link to it...
* // write_file contains the filename returned by write_file.
* callback(null, {‘file‘:write_file, ‘email‘:‘[email protected]‘});
* }
* }, function(err, results) {
* console.log(‘err = ‘, err);
* console.log(‘email_link = ‘, results.email_link);
* });
*
* // If you are using a JS minifier that mangles parameter names, `autoInject`
* // will not work with plain functions, since the parameter names will be
* // collapsed to a single letter identifier. To work around this, you can
* // explicitly specify the names of the parameters your task function needs
* // in an array, similar to Angular.js dependency injection.
*
* // This still has an advantage over plain `auto`, since the results a task
* // depends on are still spread into arguments.
* async.autoInject({
* //...
* write_file: [‘get_data‘, ‘make_folder‘, function(get_data, make_folder, callback) {
* callback(null, ‘filename‘);
* }],
* email_link: [‘write_file‘, function(write_file, callback) {
* callback(null, {‘file‘:write_file, ‘email‘:‘[email protected]‘});
* }]
* //...
* }, function(err, results) {
* console.log(‘err = ‘, err);
* console.log(‘email_link = ‘, results.email_link);
* });
*/
function autoInject(tasks, callback) {
var newTasks = {};
baseForOwn(tasks, function (taskFn, key) {
var params;
var fnIsAsync = isAsync(taskFn);
var hasNoDeps =
(!fnIsAsync && taskFn.length === 1) ||
(fnIsAsync && taskFn.length === 0);
if (isArray(taskFn)) {
params = taskFn.slice(0, -1);
taskFn = taskFn[taskFn.length - 1];
newTasks[key] = params.concat(params.length > 0 ? newTask : taskFn);
} else if (hasNoDeps) {
// no dependencies, use the function as-is
newTasks[key] = taskFn;
} else {
params = parseParams(taskFn);
if (taskFn.length === 0 && !fnIsAsync && params.length === 0) {
throw new Error("autoInject task functions require explicit parameters.");
}
// remove callback param
if (!fnIsAsync) params.pop();
newTasks[key] = params.concat(newTask);
}
function newTask(results, taskCb) {
var newArgs = arrayMap(params, function (name) {
return results[name];
});
newArgs.push(taskCb);
wrapAsync(taskFn).apply(null, newArgs);
}
});
auto(newTasks, callback);
}
// Simple doubly linked list (https://en.wikipedia.org/wiki/Doubly_linked_list) implementation
// used for queues. This implementation assumes that the node provided by the user can be modified
// to adjust the next and last properties. We implement only the minimal functionality
// for queue support.
function DLL() {
this.head = this.tail = null;
this.length = 0;
}
function setInitial(dll, node) {
dll.length = 1;
dll.head = dll.tail = node;
}
DLL.prototype.removeLink = function(node) {
if (node.prev) node.prev.next = node.next;
else this.head = node.next;
if (node.next) node.next.prev = node.prev;
else this.tail = node.prev;
node.prev = node.next = null;
this.length -= 1;
return node;
};
DLL.prototype.empty = function () {
while(this.head) this.shift();
return this;
};
DLL.prototype.insertAfter = function(node, newNode) {
newNode.prev = node;
newNode.next = node.next;
if (node.next) node.next.prev = newNode;
else this.tail = newNode;
node.next = newNode;
this.length += 1;
};
DLL.prototype.insertBefore = function(node, newNode) {
newNode.prev = node.prev;
newNode.next = node;
if (node.prev) node.prev.next = newNode;
else this.head = newNode;
node.prev = newNode;
this.length += 1;
};
DLL.prototype.unshift = function(node) {
if (this.head) this.insertBefore(this.head, node);
else setInitial(this, node);
};
DLL.prototype.push = function(node) {
if (this.tail) this.insertAfter(this.tail, node);
else setInitial(this, node);
};
DLL.prototype.shift = function() {
return this.head && this.removeLink(this.head);
};
DLL.prototype.pop = function() {
return this.tail && this.removeLink(this.tail);
};
DLL.prototype.toArray = function () {
var arr = Array(this.length);
var curr = this.head;
for(var idx = 0; idx < this.length; idx++) {
arr[idx] = curr.data;
curr = curr.next;
}
return arr;
};
DLL.prototype.remove = function (testFn) {
var curr = this.head;
while(!!curr) {
var next = curr.next;
if (testFn(curr)) {
this.removeLink(curr);
}
curr = next;
}
return this;
};
function queue(worker, concurrency, payload) {
if (concurrency == null) {
concurrency = 1;
}
else if(concurrency === 0) {
throw new Error(‘Concurrency must not be zero‘);
}
var _worker = wrapAsync(worker);
var numRunning = 0;
var workersList = [];
function _insert(data, insertAtFront, callback) {
if (callback != null && typeof callback !== ‘function‘) {
throw new Error(‘task callback must be a function‘);
}
q.started = true;
if (!isArray(data)) {
data = [data];
}
if (data.length === 0 && q.idle()) {
// call drain immediately if there are no tasks
return setImmediate$1(function() {
q.drain();
});
}
for (var i = 0, l = data.length; i < l; i++) {
var item = {
data: data[i],
callback: callback || noop
};
if (insertAtFront) {
q._tasks.unshift(item);
} else {
q._tasks.push(item);
}
}
setImmediate$1(q.process);
}
function _next(tasks) {
return function(err){
numRunning -= 1;
for (var i = 0, l = tasks.length; i < l; i++) {
var task = tasks[i];
var index = baseIndexOf(workersList, task, 0);
if (index >= 0) {
workersList.splice(index);
}
task.callback.apply(task, arguments);
if (err != null) {
q.error(err, task.data);
}
}
if (numRunning <= (q.concurrency - q.buffer) ) {
q.unsaturated();
}
if (q.idle()) {
q.drain();
}
q.process();
};
}
var isProcessing = false;
var q = {
_tasks: new DLL(),
concurrency: concurrency,
payload: payload,
saturated: noop,
unsaturated:noop,
buffer: concurrency / 4,
empty: noop,
drain: noop,
error: noop,
started: false,
paused: false,
push: function (data, callback) {
_insert(data, false, callback);
},
kill: function () {
q.drain = noop;
q._tasks.empty();
},
unshift: function (data, callback) {
_insert(data, true, callback);
},
remove: function (testFn) {
q._tasks.remove(testFn);
},
process: function () {
// Avoid trying to start too many processing operations. This can occur
// when callbacks resolve synchronously (#1267).
if (isProcessing) {
return;
}
isProcessing = true;
while(!q.paused && numRunning < q.concurrency && q._tasks.length){
var tasks = [], data = [];
var l = q._tasks.length;
if (q.payload) l = Math.min(l, q.payload);
for (var i = 0; i < l; i++) {
var node = q._tasks.shift();
tasks.push(node);
data.push(node.data);
}
numRunning += 1;
workersList.push(tasks[0]);
if (q._tasks.length === 0) {
q.empty();
}
if (numRunning === q.concurrency) {
q.saturated();
}
var cb = onlyOnce(_next(tasks));
_worker(data, cb);
}
isProcessing = false;
},
length: function () {
return q._tasks.length;
},
running: function () {
return numRunning;
},
workersList: function () {
return workersList;
},
idle: function() {
return q._tasks.length + numRunning === 0;
},
pause: function () {
q.paused = true;
},
resume: function () {
if (q.paused === false) { return; }
q.paused = false;
setImmediate$1(q.process);
}
};
return q;
}
/**
* A cargo of tasks for the worker function to complete. Cargo inherits all of
* the same methods and event callbacks as [`queue`]{@link module:ControlFlow.queue}.
* @typedef {Object} CargoObject
* @memberOf module:ControlFlow
* @property {Function} length - A function returning the number of items
* waiting to be processed. Invoke like `cargo.length()`.
* @property {number} payload - An `integer` for determining how many tasks
* should be process per round. This property can be changed after a `cargo` is
* created to alter the payload on-the-fly.
* @property {Function} push - Adds `task` to the `queue`. The callback is
* called once the `worker` has finished processing the task. Instead of a
* single task, an array of `tasks` can be submitted. The respective callback is
* used for every task in the list. Invoke like `cargo.push(task, [callback])`.
* @property {Function} saturated - A callback that is called when the
* `queue.length()` hits the concurrency and further tasks will be queued.
* @property {Function} empty - A callback that is called when the last item
* from the `queue` is given to a `worker`.
* @property {Function} drain - A callback that is called when the last item
* from the `queue` has returned from the `worker`.
* @property {Function} idle - a function returning false if there are items
* waiting or being processed, or true if not. Invoke like `cargo.idle()`.
* @property {Function} pause - a function that pauses the processing of tasks
* until `resume()` is called. Invoke like `cargo.pause()`.
* @property {Function} resume - a function that resumes the processing of
* queued tasks when the queue is paused. Invoke like `cargo.resume()`.
* @property {Function} kill - a function that removes the `drain` callback and
* empties remaining tasks from the queue forcing it to go idle. Invoke like `cargo.kill()`.
*/
/**
* Creates a `cargo` object with the specified payload. Tasks added to the
* cargo will be processed altogether (up to the `payload` limit). If the
* `worker` is in progress, the task is queued until it becomes available. Once
* the `worker` has completed some tasks, each callback of those tasks is
* called. Check out [these](https://camo.githubusercontent.com/6bbd36f4cf5b35a0f11a96dcd2e97711ffc2fb37/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130382f62626330636662302d356632392d313165322d393734662d3333393763363464633835382e676966) [animations](https://camo.githubusercontent.com/f4810e00e1c5f5f8addbe3e9f49064fd5d102699/68747470733a2f2f662e636c6f75642e6769746875622e636f6d2f6173736574732f313637363837312f36383130312f38346339323036362d356632392d313165322d383134662d3964336430323431336266642e676966)
* for how `cargo` and `queue` work.
*
* While [`queue`]{@link module:ControlFlow.queue} passes only one task to one of a group of workers
* at a time, cargo passes an array of tasks to a single worker, repeating
* when the worker is finished.
*
* @name cargo
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.queue]{@link module:ControlFlow.queue}
* @category Control Flow
* @param {AsyncFunction} worker - An asynchronous function for processing an array
* of queued tasks. Invoked with `(tasks, callback)`.
* @param {number} [payload=Infinity] - An optional `integer` for determining
* how many tasks should be processed per round; if omitted, the default is
* unlimited.
* @returns {module:ControlFlow.CargoObject} A cargo object to manage the tasks. Callbacks can
* attached as certain properties to listen for specific events during the
* lifecycle of the cargo and inner queue.
* @example
*
* // create a cargo object with payload 2
* var cargo = async.cargo(function(tasks, callback) {
* for (var i=0; i<tasks.length; i++) {
* console.log(‘hello ‘ + tasks[i].name);
* }
* callback();
* }, 2);
*
* // add some items
* cargo.push({name: ‘foo‘}, function(err) {
* console.log(‘finished processing foo‘);
* });
* cargo.push({name: ‘bar‘}, function(err) {
* console.log(‘finished processing bar‘);
* });
* cargo.push({name: ‘baz‘}, function(err) {
* console.log(‘finished processing baz‘);
* });
*/
function cargo(worker, payload) {
return queue(worker, 1, payload);
}
/**
* The same as [`eachOf`]{@link module:Collections.eachOf} but runs only a single async operation at a time.
*
* @name eachOfSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.eachOf]{@link module:Collections.eachOf}
* @alias forEachOfSeries
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* Invoked with (item, key, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. Invoked with (err).
*/
var eachOfSeries = doLimit(eachOfLimit, 1);
/**
* Reduces `coll` into a single value using an async `iteratee` to return each
* successive step. `memo` is the initial state of the reduction. This function
* only operates in series.
*
* For performance reasons, it may make sense to split a call to this function
* into a parallel map, and then use the normal `Array.prototype.reduce` on the
* results. This function is for situations where each step in the reduction
* needs to be async; if you can get the data before reducing it, then it‘s
* probably a good idea to do so.
*
* @name reduce
* @static
* @memberOf module:Collections
* @method
* @alias inject
* @alias foldl
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {*} memo - The initial state of the reduction.
* @param {AsyncFunction} iteratee - A function applied to each item in the
* array to produce the next step in the reduction.
* The `iteratee` should complete with the next state of the reduction.
* If the iteratee complete with an error, the reduction is stopped and the
* main `callback` is immediately called with the error.
* Invoked with (memo, item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Result is the reduced value. Invoked with
* (err, result).
* @example
*
* async.reduce([1,2,3], 0, function(memo, item, callback) {
* // pointless async:
* process.nextTick(function() {
* callback(null, memo + item)
* });
* }, function(err, result) {
* // result is now equal to the last value of memo, which is 6
* });
*/
function reduce(coll, memo, iteratee, callback) {
callback = once(callback || noop);
var _iteratee = wrapAsync(iteratee);
eachOfSeries(coll, function(x, i, callback) {
_iteratee(memo, x, function(err, v) {
memo = v;
callback(err);
});
}, function(err) {
callback(err, memo);
});
}
/**
* Version of the compose function that is more natural to read. Each function
* consumes the return value of the previous function. It is the equivalent of
* [compose]{@link module:ControlFlow.compose} with the arguments reversed.
*
* Each function is executed with the `this` binding of the composed function.
*
* @name seq
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.compose]{@link module:ControlFlow.compose}
* @category Control Flow
* @param {...AsyncFunction} functions - the asynchronous functions to compose
* @returns {Function} a function that composes the `functions` in order
* @example
*
* // Requires lodash (or underscore), express3 and dresende‘s orm2.
* // Part of an app, that fetches cats of the logged user.
* // This example uses `seq` function to avoid overnesting and error
* // handling clutter.
* app.get(‘/cats‘, function(request, response) {
* var User = request.models.User;
* async.seq(
* _.bind(User.get, User), // ‘User.get‘ has signature (id, callback(err, data))
* function(user, fn) {
* user.getCats(fn); // ‘getCats‘ has signature (callback(err, data))
* }
* )(req.session.user_id, function (err, cats) {
* if (err) {
* console.error(err);
* response.json({ status: ‘error‘, message: err.message });
* } else {
* response.json({ status: ‘ok‘, message: ‘Cats found‘, data: cats });
* }
* });
* });
*/
function seq(/*...functions*/) {
var _functions = arrayMap(arguments, wrapAsync);
return function(/*...args*/) {
var args = slice(arguments);
var that = this;
var cb = args[args.length - 1];
if (typeof cb == ‘function‘) {
args.pop();
} else {
cb = noop;
}
reduce(_functions, args, function(newargs, fn, cb) {
fn.apply(that, newargs.concat(function(err/*, ...nextargs*/) {
var nextargs = slice(arguments, 1);
cb(err, nextargs);
}));
},
function(err, results) {
cb.apply(that, [err].concat(results));
});
};
}
/**
* Creates a function which is a composition of the passed asynchronous
* functions. Each function consumes the return value of the function that
* follows. Composing functions `f()`, `g()`, and `h()` would produce the result
* of `f(g(h()))`, only this version uses callbacks to obtain the return values.
*
* Each function is executed with the `this` binding of the composed function.
*
* @name compose
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {...AsyncFunction} functions - the asynchronous functions to compose
* @returns {Function} an asynchronous function that is the composed
* asynchronous `functions`
* @example
*
* function add1(n, callback) {
* setTimeout(function () {
* callback(null, n + 1);
* }, 10);
* }
*
* function mul3(n, callback) {
* setTimeout(function () {
* callback(null, n * 3);
* }, 10);
* }
*
* var add1mul3 = async.compose(mul3, add1);
* add1mul3(4, function (err, result) {
* // result now equals 15
* });
*/
var compose = function(/*...args*/) {
return seq.apply(null, slice(arguments).reverse());
};
function concat$1(eachfn, arr, fn, callback) {
var result = [];
eachfn(arr, function (x, index, cb) {
fn(x, function (err, y) {
result = result.concat(y || []);
cb(err);
});
}, function (err) {
callback(err, result);
});
}
/**
* Applies `iteratee` to each item in `coll`, concatenating the results. Returns
* the concatenated list. The `iteratee`s are called in parallel, and the
* results are concatenated as they return. There is no guarantee that the
* results array will be returned in the original order of `coll` passed to the
* `iteratee` function.
*
* @name concat
* @static
* @memberOf module:Collections
* @method
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - A function to apply to each item in `coll`,
* which should use an array as its result. Invoked with (item, callback).
* @param {Function} [callback(err)] - A callback which is called after all the
* `iteratee` functions have finished, or an error occurs. Results is an array
* containing the concatenated results of the `iteratee` function. Invoked with
* (err, results).
* @example
*
* async.concat([‘dir1‘,‘dir2‘,‘dir3‘], fs.readdir, function(err, files) {
* // files is now a list of filenames that exist in the 3 directories
* });
*/
var concat = doParallel(concat$1);
function doSeries(fn) {
return function (obj, iteratee, callback) {
return fn(eachOfSeries, obj, wrapAsync(iteratee), callback);
};
}
/**
* The same as [`concat`]{@link module:Collections.concat} but runs only a single async operation at a time.
*
* @name concatSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.concat]{@link module:Collections.concat}
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - A function to apply to each item in `coll`.
* The iteratee should complete with an array an array of results.
* Invoked with (item, callback).
* @param {Function} [callback(err)] - A callback which is called after all the
* `iteratee` functions have finished, or an error occurs. Results is an array
* containing the concatenated results of the `iteratee` function. Invoked with
* (err, results).
*/
var concatSeries = doSeries(concat$1);
/**
* Returns a function that when called, calls-back with the values provided.
* Useful as the first function in a [`waterfall`]{@link module:ControlFlow.waterfall}, or for plugging values in to
* [`auto`]{@link module:ControlFlow.auto}.
*
* @name constant
* @static
* @memberOf module:Utils
* @method
* @category Util
* @param {...*} arguments... - Any number of arguments to automatically invoke
* callback with.
* @returns {AsyncFunction} Returns a function that when invoked, automatically
* invokes the callback with the previous given arguments.
* @example
*
* async.waterfall([
* async.constant(42),
* function (value, next) {
* // value === 42
* },
* //...
* ], callback);
*
* async.waterfall([
* async.constant(filename, "utf8"),
* fs.readFile,
* function (fileData, next) {
* //...
* }
* //...
* ], callback);
*
* async.auto({
* hostname: async.constant("https://server.net/"),
* port: findFreePort,
* launchServer: ["hostname", "port", function (options, cb) {
* startServer(options, cb);
* }],
* //...
* }, callback);
*/
var constant = function(/*...values*/) {
var values = slice(arguments);
var args = [null].concat(values);
return function (/*...ignoredArgs, callback*/) {
var callback = arguments[arguments.length - 1];
return callback.apply(this, args);
};
};
/**
* This method returns the first argument it receives.
*
* @static
* @since 0.1.0
* @memberOf _
* @category Util
* @param {*} value Any value.
* @returns {*} Returns `value`.
* @example
*
* var object = { ‘a‘: 1 };
*
* console.log(_.identity(object) === object);
* // => true
*/
function identity(value) {
return value;
}
function _createTester(check, getResult) {
return function(eachfn, arr, iteratee, cb) {
cb = cb || noop;
var testPassed = false;
var testResult;
eachfn(arr, function(value, _, callback) {
iteratee(value, function(err, result) {
if (err) {
callback(err);
} else if (check(result) && !testResult) {
testPassed = true;
testResult = getResult(true, value);
callback(null, breakLoop);
} else {
callback();
}
});
}, function(err) {
if (err) {
cb(err);
} else {
cb(null, testPassed ? testResult : getResult(false));
}
});
};
}
function _findGetResult(v, x) {
return x;
}
/**
* Returns the first value in `coll` that passes an async truth test. The
* `iteratee` is applied in parallel, meaning the first iteratee to return
* `true` will fire the detect `callback` with that result. That means the
* result might not be the first item in the original `coll` (in terms of order)
* that passes the test.
* If order within the original `coll` is important, then look at
* [`detectSeries`]{@link module:Collections.detectSeries}.
*
* @name detect
* @static
* @memberOf module:Collections
* @method
* @alias find
* @category Collections
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
* The iteratee must complete with a boolean value as its result.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called as soon as any
* iteratee returns `true`, or after all the `iteratee` functions have finished.
* Result will be the first item in the array that passes the truth test
* (iteratee) or the value `undefined` if none passed. Invoked with
* (err, result).
* @example
*
* async.detect([‘file1‘,‘file2‘,‘file3‘], function(filePath, callback) {
* fs.access(filePath, function(err) {
* callback(null, !err)
* });
* }, function(err, result) {
* // result now equals the first file in the list that exists
* });
*/
var detect = doParallel(_createTester(identity, _findGetResult));
/**
* The same as [`detect`]{@link module:Collections.detect} but runs a maximum of `limit` async operations at a
* time.
*
* @name detectLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.detect]{@link module:Collections.detect}
* @alias findLimit
* @category Collections
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
* The iteratee must complete with a boolean value as its result.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called as soon as any
* iteratee returns `true`, or after all the `iteratee` functions have finished.
* Result will be the first item in the array that passes the truth test
* (iteratee) or the value `undefined` if none passed. Invoked with
* (err, result).
*/
var detectLimit = doParallelLimit(_createTester(identity, _findGetResult));
/**
* The same as [`detect`]{@link module:Collections.detect} but runs only a single async operation at a time.
*
* @name detectSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.detect]{@link module:Collections.detect}
* @alias findSeries
* @category Collections
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - A truth test to apply to each item in `coll`.
* The iteratee must complete with a boolean value as its result.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called as soon as any
* iteratee returns `true`, or after all the `iteratee` functions have finished.
* Result will be the first item in the array that passes the truth test
* (iteratee) or the value `undefined` if none passed. Invoked with
* (err, result).
*/
var detectSeries = doLimit(detectLimit, 1);
function consoleFunc(name) {
return function (fn/*, ...args*/) {
var args = slice(arguments, 1);
args.push(function (err/*, ...args*/) {
var args = slice(arguments, 1);
if (typeof console === ‘object‘) {
if (err) {
if (console.error) {
console.error(err);
}
} else if (console[name]) {
arrayEach(args, function (x) {
console[name](x);
});
}
}
});
wrapAsync(fn).apply(null, args);
};
}
/**
* Logs the result of an [`async` function]{@link AsyncFunction} to the
* `console` using `console.dir` to display the properties of the resulting object.
* Only works in Node.js or in browsers that support `console.dir` and
* `console.error` (such as FF and Chrome).
* If multiple arguments are returned from the async function,
* `console.dir` is called on each argument in order.
*
* @name dir
* @static
* @memberOf module:Utils
* @method
* @category Util
* @param {AsyncFunction} function - The function you want to eventually apply
* all arguments to.
* @param {...*} arguments... - Any number of arguments to apply to the function.
* @example
*
* // in a module
* var hello = function(name, callback) {
* setTimeout(function() {
* callback(null, {hello: name});
* }, 1000);
* };
*
* // in the node repl
* node> async.dir(hello, ‘world‘);
* {hello: ‘world‘}
*/
var dir = consoleFunc(‘dir‘);
/**
* The post-check version of [`during`]{@link module:ControlFlow.during}. To reflect the difference in
* the order of operations, the arguments `test` and `fn` are switched.
*
* Also a version of [`doWhilst`]{@link module:ControlFlow.doWhilst} with asynchronous `test` function.
* @name doDuring
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.during]{@link module:ControlFlow.during}
* @category Control Flow
* @param {AsyncFunction} fn - An async function which is called each time
* `test` passes. Invoked with (callback).
* @param {AsyncFunction} test - asynchronous truth test to perform before each
* execution of `fn`. Invoked with (...args, callback), where `...args` are the
* non-error args from the previous callback of `fn`.
* @param {Function} [callback] - A callback which is called after the test
* function has failed and repeated execution of `fn` has stopped. `callback`
* will be passed an error if one occurred, otherwise `null`.
*/
function doDuring(fn, test, callback) {
callback = onlyOnce(callback || noop);
var _fn = wrapAsync(fn);
var _test = wrapAsync(test);
function next(err/*, ...args*/) {
if (err) return callback(err);
var args = slice(arguments, 1);
args.push(check);
_test.apply(this, args);
}
function check(err, truth) {
if (err) return callback(err);
if (!truth) return callback(null);
_fn(next);
}
check(null, true);
}
/**
* The post-check version of [`whilst`]{@link module:ControlFlow.whilst}. To reflect the difference in
* the order of operations, the arguments `test` and `iteratee` are switched.
*
* `doWhilst` is to `whilst` as `do while` is to `while` in plain JavaScript.
*
* @name doWhilst
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.whilst]{@link module:ControlFlow.whilst}
* @category Control Flow
* @param {AsyncFunction} iteratee - A function which is called each time `test`
* passes. Invoked with (callback).
* @param {Function} test - synchronous truth test to perform after each
* execution of `iteratee`. Invoked with any non-error callback results of
* `iteratee`.
* @param {Function} [callback] - A callback which is called after the test
* function has failed and repeated execution of `iteratee` has stopped.
* `callback` will be passed an error and any arguments passed to the final
* `iteratee`‘s callback. Invoked with (err, [results]);
*/
function doWhilst(iteratee, test, callback) {
callback = onlyOnce(callback || noop);
var _iteratee = wrapAsync(iteratee);
var next = function(err/*, ...args*/) {
if (err) return callback(err);
var args = slice(arguments, 1);
if (test.apply(this, args)) return _iteratee(next);
callback.apply(null, [null].concat(args));
};
_iteratee(next);
}
/**
* Like [‘doWhilst‘]{@link module:ControlFlow.doWhilst}, except the `test` is inverted. Note the
* argument ordering differs from `until`.
*
* @name doUntil
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.doWhilst]{@link module:ControlFlow.doWhilst}
* @category Control Flow
* @param {AsyncFunction} iteratee - An async function which is called each time
* `test` fails. Invoked with (callback).
* @param {Function} test - synchronous truth test to perform after each
* execution of `iteratee`. Invoked with any non-error callback results of
* `iteratee`.
* @param {Function} [callback] - A callback which is called after the test
* function has passed and repeated execution of `iteratee` has stopped. `callback`
* will be passed an error and any arguments passed to the final `iteratee`‘s
* callback. Invoked with (err, [results]);
*/
function doUntil(iteratee, test, callback) {
doWhilst(iteratee, function() {
return !test.apply(this, arguments);
}, callback);
}
/**
* Like [`whilst`]{@link module:ControlFlow.whilst}, except the `test` is an asynchronous function that
* is passed a callback in the form of `function (err, truth)`. If error is
* passed to `test` or `fn`, the main callback is immediately called with the
* value of the error.
*
* @name during
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.whilst]{@link module:ControlFlow.whilst}
* @category Control Flow
* @param {AsyncFunction} test - asynchronous truth test to perform before each
* execution of `fn`. Invoked with (callback).
* @param {AsyncFunction} fn - An async function which is called each time
* `test` passes. Invoked with (callback).
* @param {Function} [callback] - A callback which is called after the test
* function has failed and repeated execution of `fn` has stopped. `callback`
* will be passed an error, if one occurred, otherwise `null`.
* @example
*
* var count = 0;
*
* async.during(
* function (callback) {
* return callback(null, count < 5);
* },
* function (callback) {
* count++;
* setTimeout(callback, 1000);
* },
* function (err) {
* // 5 seconds have passed
* }
* );
*/
function during(test, fn, callback) {
callback = onlyOnce(callback || noop);
var _fn = wrapAsync(fn);
var _test = wrapAsync(test);
function next(err) {
if (err) return callback(err);
_test(check);
}
function check(err, truth) {
if (err) return callback(err);
if (!truth) return callback(null);
_fn(next);
}
_test(check);
}
function _withoutIndex(iteratee) {
return function (value, index, callback) {
return iteratee(value, callback);
};
}
/**
* Applies the function `iteratee` to each item in `coll`, in parallel.
* The `iteratee` is called with an item from the list, and a callback for when
* it has finished. If the `iteratee` passes an error to its `callback`, the
* main `callback` (for the `each` function) is immediately called with the
* error.
*
* Note, that since this function applies `iteratee` to each item in parallel,
* there is no guarantee that the iteratee functions will complete in order.
*
* @name each
* @static
* @memberOf module:Collections
* @method
* @alias forEach
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async function to apply to
* each item in `coll`. Invoked with (item, callback).
* The array index is not passed to the iteratee.
* If you need the index, use `eachOf`.
* @param {Function} [callback] - A callback which is called when all
* `iteratee` functions have finished, or an error occurs. Invoked with (err).
* @example
*
* // assuming openFiles is an array of file names and saveFile is a function
* // to save the modified contents of that file:
*
* async.each(openFiles, saveFile, function(err){
* // if any of the saves produced an error, err would equal that error
* });
*
* // assuming openFiles is an array of file names
* async.each(openFiles, function(file, callback) {
*
* // Perform operation on file here.
* console.log(‘Processing file ‘ + file);
*
* if( file.length > 32 ) {
* console.log(‘This file name is too long‘);
* callback(‘File name too long‘);
* } else {
* // Do work to process file here
* console.log(‘File processed‘);
* callback();
* }
* }, function(err) {
* // if any of the file processing produced an error, err would equal that error
* if( err ) {
* // One of the iterations produced an error.
* // All processing will now stop.
* console.log(‘A file failed to process‘);
* } else {
* console.log(‘All files have been processed successfully‘);
* }
* });
*/
function eachLimit(coll, iteratee, callback) {
eachOf(coll, _withoutIndex(wrapAsync(iteratee)), callback);
}
/**
* The same as [`each`]{@link module:Collections.each} but runs a maximum of `limit` async operations at a time.
*
* @name eachLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.each]{@link module:Collections.each}
* @alias forEachLimit
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* The array index is not passed to the iteratee.
* If you need the index, use `eachOfLimit`.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called when all
* `iteratee` functions have finished, or an error occurs. Invoked with (err).
*/
function eachLimit$1(coll, limit, iteratee, callback) {
_eachOfLimit(limit)(coll, _withoutIndex(wrapAsync(iteratee)), callback);
}
/**
* The same as [`each`]{@link module:Collections.each} but runs only a single async operation at a time.
*
* @name eachSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.each]{@link module:Collections.each}
* @alias forEachSeries
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async function to apply to each
* item in `coll`.
* The array index is not passed to the iteratee.
* If you need the index, use `eachOfSeries`.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called when all
* `iteratee` functions have finished, or an error occurs. Invoked with (err).
*/
var eachSeries = doLimit(eachLimit$1, 1);
/**
* Wrap an async function and ensure it calls its callback on a later tick of
* the event loop. If the function already calls its callback on a next tick,
* no extra deferral is added. This is useful for preventing stack overflows
* (`RangeError: Maximum call stack size exceeded`) and generally keeping
* [Zalgo](http://blog.izs.me/post/59142742143/designing-apis-for-asynchrony)
* contained. ES2017 `async` functions are returned as-is -- they are immune
* to Zalgo‘s corrupting influences, as they always resolve on a later tick.
*
* @name ensureAsync
* @static
* @memberOf module:Utils
* @method
* @category Util
* @param {AsyncFunction} fn - an async function, one that expects a node-style
* callback as its last argument.
* @returns {AsyncFunction} Returns a wrapped function with the exact same call
* signature as the function passed in.
* @example
*
* function sometimesAsync(arg, callback) {
* if (cache[arg]) {
* return callback(null, cache[arg]); // this would be synchronous!!
* } else {
* doSomeIO(arg, callback); // this IO would be asynchronous
* }
* }
*
* // this has a risk of stack overflows if many results are cached in a row
* async.mapSeries(args, sometimesAsync, done);
*
* // this will defer sometimesAsync‘s callback if necessary,
* // preventing stack overflows
* async.mapSeries(args, async.ensureAsync(sometimesAsync), done);
*/
function ensureAsync(fn) {
if (isAsync(fn)) return fn;
return initialParams(function (args, callback) {
var sync = true;
args.push(function () {
var innerArgs = arguments;
if (sync) {
setImmediate$1(function () {
callback.apply(null, innerArgs);
});
} else {
callback.apply(null, innerArgs);
}
});
fn.apply(this, args);
sync = false;
});
}
function notId(v) {
return !v;
}
/**
* Returns `true` if every element in `coll` satisfies an async test. If any
* iteratee call returns `false`, the main `callback` is immediately called.
*
* @name every
* @static
* @memberOf module:Collections
* @method
* @alias all
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async truth test to apply to each item
* in the collection in parallel.
* The iteratee must complete with a boolean result value.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Result will be either `true` or `false`
* depending on the values of the async tests. Invoked with (err, result).
* @example
*
* async.every([‘file1‘,‘file2‘,‘file3‘], function(filePath, callback) {
* fs.access(filePath, function(err) {
* callback(null, !err)
* });
* }, function(err, result) {
* // if result is true then every file exists
* });
*/
var every = doParallel(_createTester(notId, notId));
/**
* The same as [`every`]{@link module:Collections.every} but runs a maximum of `limit` async operations at a time.
*
* @name everyLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.every]{@link module:Collections.every}
* @alias allLimit
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - An async truth test to apply to each item
* in the collection in parallel.
* The iteratee must complete with a boolean result value.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Result will be either `true` or `false`
* depending on the values of the async tests. Invoked with (err, result).
*/
var everyLimit = doParallelLimit(_createTester(notId, notId));
/**
* The same as [`every`]{@link module:Collections.every} but runs only a single async operation at a time.
*
* @name everySeries
* @static
* @memberOf module:Collections
* @method
* @see [async.every]{@link module:Collections.every}
* @alias allSeries
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async truth test to apply to each item
* in the collection in series.
* The iteratee must complete with a boolean result value.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Result will be either `true` or `false`
* depending on the values of the async tests. Invoked with (err, result).
*/
var everySeries = doLimit(everyLimit, 1);
/**
* The base implementation of `_.property` without support for deep paths.
*
* @private
* @param {string} key The key of the property to get.
* @returns {Function} Returns the new accessor function.
*/
function baseProperty(key) {
return function(object) {
return object == null ? undefined : object[key];
};
}
function filterArray(eachfn, arr, iteratee, callback) {
var truthValues = new Array(arr.length);
eachfn(arr, function (x, index, callback) {
iteratee(x, function (err, v) {
truthValues[index] = !!v;
callback(err);
});
}, function (err) {
if (err) return callback(err);
var results = [];
for (var i = 0; i < arr.length; i++) {
if (truthValues[i]) results.push(arr[i]);
}
callback(null, results);
});
}
function filterGeneric(eachfn, coll, iteratee, callback) {
var results = [];
eachfn(coll, function (x, index, callback) {
iteratee(x, function (err, v) {
if (err) {
callback(err);
} else {
if (v) {
results.push({index: index, value: x});
}
callback();
}
});
}, function (err) {
if (err) {
callback(err);
} else {
callback(null, arrayMap(results.sort(function (a, b) {
return a.index - b.index;
}), baseProperty(‘value‘)));
}
});
}
function _filter(eachfn, coll, iteratee, callback) {
var filter = isArrayLike(coll) ? filterArray : filterGeneric;
filter(eachfn, coll, wrapAsync(iteratee), callback || noop);
}
/**
* Returns a new array of all the values in `coll` which pass an async truth
* test. This operation is performed in parallel, but the results array will be
* in the same order as the original.
*
* @name filter
* @static
* @memberOf module:Collections
* @method
* @alias select
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {Function} iteratee - A truth test to apply to each item in `coll`.
* The `iteratee` is passed a `callback(err, truthValue)`, which must be called
* with a boolean argument once it has completed. Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Invoked with (err, results).
* @example
*
* async.filter([‘file1‘,‘file2‘,‘file3‘], function(filePath, callback) {
* fs.access(filePath, function(err) {
* callback(null, !err)
* });
* }, function(err, results) {
* // results now equals an array of the existing files
* });
*/
var filter = doParallel(_filter);
/**
* The same as [`filter`]{@link module:Collections.filter} but runs a maximum of `limit` async operations at a
* time.
*
* @name filterLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.filter]{@link module:Collections.filter}
* @alias selectLimit
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {Function} iteratee - A truth test to apply to each item in `coll`.
* The `iteratee` is passed a `callback(err, truthValue)`, which must be called
* with a boolean argument once it has completed. Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Invoked with (err, results).
*/
var filterLimit = doParallelLimit(_filter);
/**
* The same as [`filter`]{@link module:Collections.filter} but runs only a single async operation at a time.
*
* @name filterSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.filter]{@link module:Collections.filter}
* @alias selectSeries
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {Function} iteratee - A truth test to apply to each item in `coll`.
* The `iteratee` is passed a `callback(err, truthValue)`, which must be called
* with a boolean argument once it has completed. Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Invoked with (err, results)
*/
var filterSeries = doLimit(filterLimit, 1);
/**
* Calls the asynchronous function `fn` with a callback parameter that allows it
* to call itself again, in series, indefinitely.
* If an error is passed to the callback then `errback` is called with the
* error, and execution stops, otherwise it will never be called.
*
* @name forever
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {AsyncFunction} fn - an async function to call repeatedly.
* Invoked with (next).
* @param {Function} [errback] - when `fn` passes an error to it‘s callback,
* this function will be called, and execution stops. Invoked with (err).
* @example
*
* async.forever(
* function(next) {
* // next is suitable for passing to things that need a callback(err [, whatever]);
* // it will result in this function being called again.
* },
* function(err) {
* // if next is called with a value in its first parameter, it will appear
* // in here as ‘err‘, and execution will stop.
* }
* );
*/
function forever(fn, errback) {
var done = onlyOnce(errback || noop);
var task = wrapAsync(ensureAsync(fn));
function next(err) {
if (err) return done(err);
task(next);
}
next();
}
/**
* The same as [`groupBy`]{@link module:Collections.groupBy} but runs a maximum of `limit` async operations at a time.
*
* @name groupByLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.groupBy]{@link module:Collections.groupBy}
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* The iteratee should complete with a `key` to group the value under.
* Invoked with (value, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. Result is an `Object` whoses
* properties are arrays of values which returned the corresponding key.
*/
var groupByLimit = function(coll, limit, iteratee, callback) {
callback = callback || noop;
var _iteratee = wrapAsync(iteratee);
mapLimit(coll, limit, function(val, callback) {
_iteratee(val, function(err, key) {
if (err) return callback(err);
return callback(null, {key: key, val: val});
});
}, function(err, mapResults) {
var result = {};
// from MDN, handle object having an `hasOwnProperty` prop
var hasOwnProperty = Object.prototype.hasOwnProperty;
for (var i = 0; i < mapResults.length; i++) {
if (mapResults[i]) {
var key = mapResults[i].key;
var val = mapResults[i].val;
if (hasOwnProperty.call(result, key)) {
result[key].push(val);
} else {
result[key] = [val];
}
}
}
return callback(err, result);
});
};
/**
* Returns a new object, where each value corresponds to an array of items, from
* `coll`, that returned the corresponding key. That is, the keys of the object
* correspond to the values passed to the `iteratee` callback.
*
* Note: Since this function applies the `iteratee` to each item in parallel,
* there is no guarantee that the `iteratee` functions will complete in order.
* However, the values for each key in the `result` will be in the same order as
* the original `coll`. For Objects, the values will roughly be in the order of
* the original Objects‘ keys (but this can vary across JavaScript engines).
*
* @name groupBy
* @static
* @memberOf module:Collections
* @method
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* The iteratee should complete with a `key` to group the value under.
* Invoked with (value, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. Result is an `Object` whoses
* properties are arrays of values which returned the corresponding key.
* @example
*
* async.groupBy([‘userId1‘, ‘userId2‘, ‘userId3‘], function(userId, callback) {
* db.findById(userId, function(err, user) {
* if (err) return callback(err);
* return callback(null, user.age);
* });
* }, function(err, result) {
* // result is object containing the userIds grouped by age
* // e.g. { 30: [‘userId1‘, ‘userId3‘], 42: [‘userId2‘]};
* });
*/
var groupBy = doLimit(groupByLimit, Infinity);
/**
* The same as [`groupBy`]{@link module:Collections.groupBy} but runs only a single async operation at a time.
*
* @name groupBySeries
* @static
* @memberOf module:Collections
* @method
* @see [async.groupBy]{@link module:Collections.groupBy}
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* The iteratee should complete with a `key` to group the value under.
* Invoked with (value, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. Result is an `Object` whoses
* properties are arrays of values which returned the corresponding key.
*/
var groupBySeries = doLimit(groupByLimit, 1);
/**
* Logs the result of an `async` function to the `console`. Only works in
* Node.js or in browsers that support `console.log` and `console.error` (such
* as FF and Chrome). If multiple arguments are returned from the async
* function, `console.log` is called on each argument in order.
*
* @name log
* @static
* @memberOf module:Utils
* @method
* @category Util
* @param {AsyncFunction} function - The function you want to eventually apply
* all arguments to.
* @param {...*} arguments... - Any number of arguments to apply to the function.
* @example
*
* // in a module
* var hello = function(name, callback) {
* setTimeout(function() {
* callback(null, ‘hello ‘ + name);
* }, 1000);
* };
*
* // in the node repl
* node> async.log(hello, ‘world‘);
* ‘hello world‘
*/
var log = consoleFunc(‘log‘);
/**
* The same as [`mapValues`]{@link module:Collections.mapValues} but runs a maximum of `limit` async operations at a
* time.
*
* @name mapValuesLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.mapValues]{@link module:Collections.mapValues}
* @category Collection
* @param {Object} obj - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - A function to apply to each value and key
* in `coll`.
* The iteratee should complete with the transformed value as its result.
* Invoked with (value, key, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. `result` is a new object consisting
* of each key from `obj`, with each transformed value on the right-hand side.
* Invoked with (err, result).
*/
function mapValuesLimit(obj, limit, iteratee, callback) {
callback = once(callback || noop);
var newObj = {};
var _iteratee = wrapAsync(iteratee);
eachOfLimit(obj, limit, function(val, key, next) {
_iteratee(val, key, function (err, result) {
if (err) return next(err);
newObj[key] = result;
next();
});
}, function (err) {
callback(err, newObj);
});
}
/**
* A relative of [`map`]{@link module:Collections.map}, designed for use with objects.
*
* Produces a new Object by mapping each value of `obj` through the `iteratee`
* function. The `iteratee` is called each `value` and `key` from `obj` and a
* callback for when it has finished processing. Each of these callbacks takes
* two arguments: an `error`, and the transformed item from `obj`. If `iteratee`
* passes an error to its callback, the main `callback` (for the `mapValues`
* function) is immediately called with the error.
*
* Note, the order of the keys in the result is not guaranteed. The keys will
* be roughly in the order they complete, (but this is very engine-specific)
*
* @name mapValues
* @static
* @memberOf module:Collections
* @method
* @category Collection
* @param {Object} obj - A collection to iterate over.
* @param {AsyncFunction} iteratee - A function to apply to each value and key
* in `coll`.
* The iteratee should complete with the transformed value as its result.
* Invoked with (value, key, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. `result` is a new object consisting
* of each key from `obj`, with each transformed value on the right-hand side.
* Invoked with (err, result).
* @example
*
* async.mapValues({
* f1: ‘file1‘,
* f2: ‘file2‘,
* f3: ‘file3‘
* }, function (file, key, callback) {
* fs.stat(file, callback);
* }, function(err, result) {
* // result is now a map of stats for each file, e.g.
* // {
* // f1: [stats for file1],
* // f2: [stats for file2],
* // f3: [stats for file3]
* // }
* });
*/
var mapValues = doLimit(mapValuesLimit, Infinity);
/**
* The same as [`mapValues`]{@link module:Collections.mapValues} but runs only a single async operation at a time.
*
* @name mapValuesSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.mapValues]{@link module:Collections.mapValues}
* @category Collection
* @param {Object} obj - A collection to iterate over.
* @param {AsyncFunction} iteratee - A function to apply to each value and key
* in `coll`.
* The iteratee should complete with the transformed value as its result.
* Invoked with (value, key, callback).
* @param {Function} [callback] - A callback which is called when all `iteratee`
* functions have finished, or an error occurs. `result` is a new object consisting
* of each key from `obj`, with each transformed value on the right-hand side.
* Invoked with (err, result).
*/
var mapValuesSeries = doLimit(mapValuesLimit, 1);
function has(obj, key) {
return key in obj;
}
/**
* Caches the results of an async function. When creating a hash to store
* function results against, the callback is omitted from the hash and an
* optional hash function can be used.
*
* If no hash function is specified, the first argument is used as a hash key,
* which may work reasonably if it is a string or a data type that converts to a
* distinct string. Note that objects and arrays will not behave reasonably.
* Neither will cases where the other arguments are significant. In such cases,
* specify your own hash function.
*
* The cache of results is exposed as the `memo` property of the function
* returned by `memoize`.
*
* @name memoize
* @static
* @memberOf module:Utils
* @method
* @category Util
* @param {AsyncFunction} fn - The async function to proxy and cache results from.
* @param {Function} hasher - An optional function for generating a custom hash
* for storing results. It has all the arguments applied to it apart from the
* callback, and must be synchronous.
* @returns {AsyncFunction} a memoized version of `fn`
* @example
*
* var slow_fn = function(name, callback) {
* // do something
* callback(null, result);
* };
* var fn = async.memoize(slow_fn);
*
* // fn can now be used as if it were slow_fn
* fn(‘some name‘, function() {
* // callback
* });
*/
function memoize(fn, hasher) {
var memo = Object.create(null);
var queues = Object.create(null);
hasher = hasher || identity;
var _fn = wrapAsync(fn);
var memoized = initialParams(function memoized(args, callback) {
var key = hasher.apply(null, args);
if (has(memo, key)) {
setImmediate$1(function() {
callback.apply(null, memo[key]);
});
} else if (has(queues, key)) {
queues[key].push(callback);
} else {
queues[key] = [callback];
_fn.apply(null, args.concat(function(/*args*/) {
var args = slice(arguments);
memo[key] = args;
var q = queues[key];
delete queues[key];
for (var i = 0, l = q.length; i < l; i++) {
q[i].apply(null, args);
}
}));
}
});
memoized.memo = memo;
memoized.unmemoized = fn;
return memoized;
}
/**
* Calls `callback` on a later loop around the event loop. In Node.js this just
* calls `setImmediate`. In the browser it will use `setImmediate` if
* available, otherwise `setTimeout(callback, 0)`, which means other higher
* priority events may precede the execution of `callback`.
*
* This is used internally for browser-compatibility purposes.
*
* @name nextTick
* @static
* @memberOf module:Utils
* @method
* @alias setImmediate
* @category Util
* @param {Function} callback - The function to call on a later loop around
* the event loop. Invoked with (args...).
* @param {...*} args... - any number of additional arguments to pass to the
* callback on the next tick.
* @example
*
* var call_order = [];
* async.nextTick(function() {
* call_order.push(‘two‘);
* // call_order now equals [‘one‘,‘two‘]
* });
* call_order.push(‘one‘);
*
* async.setImmediate(function (a, b, c) {
* // a, b, and c equal 1, 2, and 3
* }, 1, 2, 3);
*/
var _defer$1;
if (hasNextTick) {
_defer$1 = process.nextTick;
} else if (hasSetImmediate) {
_defer$1 = setImmediate;
} else {
_defer$1 = fallback;
}
var nextTick = wrap(_defer$1);
function _parallel(eachfn, tasks, callback) {
callback = callback || noop;
var results = isArrayLike(tasks) ? [] : {};
eachfn(tasks, function (task, key, callback) {
wrapAsync(task)(function (err, result) {
if (arguments.length > 2) {
result = slice(arguments, 1);
}
results[key] = result;
callback(err);
});
}, function (err) {
callback(err, results);
});
}
/**
* Run the `tasks` collection of functions in parallel, without waiting until
* the previous function has completed. If any of the functions pass an error to
* its callback, the main `callback` is immediately called with the value of the
* error. Once the `tasks` have completed, the results are passed to the final
* `callback` as an array.
*
* **Note:** `parallel` is about kicking-off I/O tasks in parallel, not about
* parallel execution of code. If your tasks do not use any timers or perform
* any I/O, they will actually be executed in series. Any synchronous setup
* sections for each task will happen one after the other. JavaScript remains
* single-threaded.
*
* **Hint:** Use [`reflect`]{@link module:Utils.reflect} to continue the
* execution of other tasks when a task fails.
*
* It is also possible to use an object instead of an array. Each property will
* be run as a function and the results will be passed to the final `callback`
* as an object instead of an array. This can be a more readable way of handling
* results from {@link async.parallel}.
*
* @name parallel
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Array|Iterable|Object} tasks - A collection of
* [async functions]{@link AsyncFunction} to run.
* Each async function can complete with any number of optional `result` values.
* @param {Function} [callback] - An optional callback to run once all the
* functions have completed successfully. This function gets a results array
* (or object) containing all the result arguments passed to the task callbacks.
* Invoked with (err, results).
*
* @example
* async.parallel([
* function(callback) {
* setTimeout(function() {
* callback(null, ‘one‘);
* }, 200);
* },
* function(callback) {
* setTimeout(function() {
* callback(null, ‘two‘);
* }, 100);
* }
* ],
* // optional callback
* function(err, results) {
* // the results array will equal [‘one‘,‘two‘] even though
* // the second function had a shorter timeout.
* });
*
* // an example using an object instead of an array
* async.parallel({
* one: function(callback) {
* setTimeout(function() {
* callback(null, 1);
* }, 200);
* },
* two: function(callback) {
* setTimeout(function() {
* callback(null, 2);
* }, 100);
* }
* }, function(err, results) {
* // results is now equals to: {one: 1, two: 2}
* });
*/
function parallelLimit(tasks, callback) {
_parallel(eachOf, tasks, callback);
}
/**
* The same as [`parallel`]{@link module:ControlFlow.parallel} but runs a maximum of `limit` async operations at a
* time.
*
* @name parallelLimit
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.parallel]{@link module:ControlFlow.parallel}
* @category Control Flow
* @param {Array|Iterable|Object} tasks - A collection of
* [async functions]{@link AsyncFunction} to run.
* Each async function can complete with any number of optional `result` values.
* @param {number} limit - The maximum number of async operations at a time.
* @param {Function} [callback] - An optional callback to run once all the
* functions have completed successfully. This function gets a results array
* (or object) containing all the result arguments passed to the task callbacks.
* Invoked with (err, results).
*/
function parallelLimit$1(tasks, limit, callback) {
_parallel(_eachOfLimit(limit), tasks, callback);
}
/**
* A queue of tasks for the worker function to complete.
* @typedef {Object} QueueObject
* @memberOf module:ControlFlow
* @property {Function} length - a function returning the number of items
* waiting to be processed. Invoke with `queue.length()`.
* @property {boolean} started - a boolean indicating whether or not any
* items have been pushed and processed by the queue.
* @property {Function} running - a function returning the number of items
* currently being processed. Invoke with `queue.running()`.
* @property {Function} workersList - a function returning the array of items
* currently being processed. Invoke with `queue.workersList()`.
* @property {Function} idle - a function returning false if there are items
* waiting or being processed, or true if not. Invoke with `queue.idle()`.
* @property {number} concurrency - an integer for determining how many `worker`
* functions should be run in parallel. This property can be changed after a
* `queue` is created to alter the concurrency on-the-fly.
* @property {Function} push - add a new task to the `queue`. Calls `callback`
* once the `worker` has finished processing the task. Instead of a single task,
* a `tasks` array can be submitted. The respective callback is used for every
* task in the list. Invoke with `queue.push(task, [callback])`,
* @property {Function} unshift - add a new task to the front of the `queue`.
* Invoke with `queue.unshift(task, [callback])`.
* @property {Function} remove - remove items from the queue that match a test
* function. The test function will be passed an object with a `data` property,
* and a `priority` property, if this is a
* [priorityQueue]{@link module:ControlFlow.priorityQueue} object.
* Invoked with `queue.remove(testFn)`, where `testFn` is of the form
* `function ({data, priority}) {}` and returns a Boolean.
* @property {Function} saturated - a callback that is called when the number of
* running workers hits the `concurrency` limit, and further tasks will be
* queued.
* @property {Function} unsaturated - a callback that is called when the number
* of running workers is less than the `concurrency` & `buffer` limits, and
* further tasks will not be queued.
* @property {number} buffer - A minimum threshold buffer in order to say that
* the `queue` is `unsaturated`.
* @property {Function} empty - a callback that is called when the last item
* from the `queue` is given to a `worker`.
* @property {Function} drain - a callback that is called when the last item
* from the `queue` has returned from the `worker`.
* @property {Function} error - a callback that is called when a task errors.
* Has the signature `function(error, task)`.
* @property {boolean} paused - a boolean for determining whether the queue is
* in a paused state.
* @property {Function} pause - a function that pauses the processing of tasks
* until `resume()` is called. Invoke with `queue.pause()`.
* @property {Function} resume - a function that resumes the processing of
* queued tasks when the queue is paused. Invoke with `queue.resume()`.
* @property {Function} kill - a function that removes the `drain` callback and
* empties remaining tasks from the queue forcing it to go idle. Invoke with `queue.kill()`.
*/
/**
* Creates a `queue` object with the specified `concurrency`. Tasks added to the
* `queue` are processed in parallel (up to the `concurrency` limit). If all
* `worker`s are in progress, the task is queued until one becomes available.
* Once a `worker` completes a `task`, that `task`‘s callback is called.
*
* @name queue
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {AsyncFunction} worker - An async function for processing a queued task.
* If you want to handle errors from an individual task, pass a callback to
* `q.push()`. Invoked with (task, callback).
* @param {number} [concurrency=1] - An `integer` for determining how many
* `worker` functions should be run in parallel. If omitted, the concurrency
* defaults to `1`. If the concurrency is `0`, an error is thrown.
* @returns {module:ControlFlow.QueueObject} A queue object to manage the tasks. Callbacks can
* attached as certain properties to listen for specific events during the
* lifecycle of the queue.
* @example
*
* // create a queue object with concurrency 2
* var q = async.queue(function(task, callback) {
* console.log(‘hello ‘ + task.name);
* callback();
* }, 2);
*
* // assign a callback
* q.drain = function() {
* console.log(‘all items have been processed‘);
* };
*
* // add some items to the queue
* q.push({name: ‘foo‘}, function(err) {
* console.log(‘finished processing foo‘);
* });
* q.push({name: ‘bar‘}, function (err) {
* console.log(‘finished processing bar‘);
* });
*
* // add some items to the queue (batch-wise)
* q.push([{name: ‘baz‘},{name: ‘bay‘},{name: ‘bax‘}], function(err) {
* console.log(‘finished processing item‘);
* });
*
* // add some items to the front of the queue
* q.unshift({name: ‘bar‘}, function (err) {
* console.log(‘finished processing bar‘);
* });
*/
var queue$1 = function (worker, concurrency) {
var _worker = wrapAsync(worker);
return queue(function (items, cb) {
_worker(items[0], cb);
}, concurrency, 1);
};
/**
* The same as [async.queue]{@link module:ControlFlow.queue} only tasks are assigned a priority and
* completed in ascending priority order.
*
* @name priorityQueue
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.queue]{@link module:ControlFlow.queue}
* @category Control Flow
* @param {AsyncFunction} worker - An async function for processing a queued task.
* If you want to handle errors from an individual task, pass a callback to
* `q.push()`.
* Invoked with (task, callback).
* @param {number} concurrency - An `integer` for determining how many `worker`
* functions should be run in parallel. If omitted, the concurrency defaults to
* `1`. If the concurrency is `0`, an error is thrown.
* @returns {module:ControlFlow.QueueObject} A priorityQueue object to manage the tasks. There are two
* differences between `queue` and `priorityQueue` objects:
* * `push(task, priority, [callback])` - `priority` should be a number. If an
* array of `tasks` is given, all tasks will be assigned the same priority.
* * The `unshift` method was removed.
*/
var priorityQueue = function(worker, concurrency) {
// Start with a normal queue
var q = queue$1(worker, concurrency);
// Override push to accept second parameter representing priority
q.push = function(data, priority, callback) {
if (callback == null) callback = noop;
if (typeof callback !== ‘function‘) {
throw new Error(‘task callback must be a function‘);
}
q.started = true;
if (!isArray(data)) {
data = [data];
}
if (data.length === 0) {
// call drain immediately if there are no tasks
return setImmediate$1(function() {
q.drain();
});
}
priority = priority || 0;
var nextNode = q._tasks.head;
while (nextNode && priority >= nextNode.priority) {
nextNode = nextNode.next;
}
for (var i = 0, l = data.length; i < l; i++) {
var item = {
data: data[i],
priority: priority,
callback: callback
};
if (nextNode) {
q._tasks.insertBefore(nextNode, item);
} else {
q._tasks.push(item);
}
}
setImmediate$1(q.process);
};
// Remove unshift function
delete q.unshift;
return q;
};
/**
* Runs the `tasks` array of functions in parallel, without waiting until the
* previous function has completed. Once any of the `tasks` complete or pass an
* error to its callback, the main `callback` is immediately called. It‘s
* equivalent to `Promise.race()`.
*
* @name race
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Array} tasks - An array containing [async functions]{@link AsyncFunction}
* to run. Each function can complete with an optional `result` value.
* @param {Function} callback - A callback to run once any of the functions have
* completed. This function gets an error or result from the first function that
* completed. Invoked with (err, result).
* @returns undefined
* @example
*
* async.race([
* function(callback) {
* setTimeout(function() {
* callback(null, ‘one‘);
* }, 200);
* },
* function(callback) {
* setTimeout(function() {
* callback(null, ‘two‘);
* }, 100);
* }
* ],
* // main callback
* function(err, result) {
* // the result will be equal to ‘two‘ as it finishes earlier
* });
*/
function race(tasks, callback) {
callback = once(callback || noop);
if (!isArray(tasks)) return callback(new TypeError(‘First argument to race must be an array of functions‘));
if (!tasks.length) return callback();
for (var i = 0, l = tasks.length; i < l; i++) {
wrapAsync(tasks[i])(callback);
}
}
/**
* Same as [`reduce`]{@link module:Collections.reduce}, only operates on `array` in reverse order.
*
* @name reduceRight
* @static
* @memberOf module:Collections
* @method
* @see [async.reduce]{@link module:Collections.reduce}
* @alias foldr
* @category Collection
* @param {Array} array - A collection to iterate over.
* @param {*} memo - The initial state of the reduction.
* @param {AsyncFunction} iteratee - A function applied to each item in the
* array to produce the next step in the reduction.
* The `iteratee` should complete with the next state of the reduction.
* If the iteratee complete with an error, the reduction is stopped and the
* main `callback` is immediately called with the error.
* Invoked with (memo, item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Result is the reduced value. Invoked with
* (err, result).
*/
function reduceRight (array, memo, iteratee, callback) {
var reversed = slice(array).reverse();
reduce(reversed, memo, iteratee, callback);
}
/**
* Wraps the async function in another function that always completes with a
* result object, even when it errors.
*
* The result object has either the property `error` or `value`.
*
* @name reflect
* @static
* @memberOf module:Utils
* @method
* @category Util
* @param {AsyncFunction} fn - The async function you want to wrap
* @returns {Function} - A function that always passes null to it‘s callback as
* the error. The second argument to the callback will be an `object` with
* either an `error` or a `value` property.
* @example
*
* async.parallel([
* async.reflect(function(callback) {
* // do some stuff ...
* callback(null, ‘one‘);
* }),
* async.reflect(function(callback) {
* // do some more stuff but error ...
* callback(‘bad stuff happened‘);
* }),
* async.reflect(function(callback) {
* // do some more stuff ...
* callback(null, ‘two‘);
* })
* ],
* // optional callback
* function(err, results) {
* // values
* // results[0].value = ‘one‘
* // results[1].error = ‘bad stuff happened‘
* // results[2].value = ‘two‘
* });
*/
function reflect(fn) {
var _fn = wrapAsync(fn);
return initialParams(function reflectOn(args, reflectCallback) {
args.push(function callback(error, cbArg) {
if (error) {
reflectCallback(null, { error: error });
} else {
var value;
if (arguments.length <= 2) {
value = cbArg;
} else {
value = slice(arguments, 1);
}
reflectCallback(null, { value: value });
}
});
return _fn.apply(this, args);
});
}
function reject$1(eachfn, arr, iteratee, callback) {
_filter(eachfn, arr, function(value, cb) {
iteratee(value, function(err, v) {
cb(err, !v);
});
}, callback);
}
/**
* The opposite of [`filter`]{@link module:Collections.filter}. Removes values that pass an `async` truth test.
*
* @name reject
* @static
* @memberOf module:Collections
* @method
* @see [async.filter]{@link module:Collections.filter}
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {Function} iteratee - An async truth test to apply to each item in
* `coll`.
* The should complete with a boolean value as its `result`.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Invoked with (err, results).
* @example
*
* async.reject([‘file1‘,‘file2‘,‘file3‘], function(filePath, callback) {
* fs.access(filePath, function(err) {
* callback(null, !err)
* });
* }, function(err, results) {
* // results now equals an array of missing files
* createFiles(results);
* });
*/
var reject = doParallel(reject$1);
/**
* A helper function that wraps an array or an object of functions with `reflect`.
*
* @name reflectAll
* @static
* @memberOf module:Utils
* @method
* @see [async.reflect]{@link module:Utils.reflect}
* @category Util
* @param {Array|Object|Iterable} tasks - The collection of
* [async functions]{@link AsyncFunction} to wrap in `async.reflect`.
* @returns {Array} Returns an array of async functions, each wrapped in
* `async.reflect`
* @example
*
* let tasks = [
* function(callback) {
* setTimeout(function() {
* callback(null, ‘one‘);
* }, 200);
* },
* function(callback) {
* // do some more stuff but error ...
* callback(new Error(‘bad stuff happened‘));
* },
* function(callback) {
* setTimeout(function() {
* callback(null, ‘two‘);
* }, 100);
* }
* ];
*
* async.parallel(async.reflectAll(tasks),
* // optional callback
* function(err, results) {
* // values
* // results[0].value = ‘one‘
* // results[1].error = Error(‘bad stuff happened‘)
* // results[2].value = ‘two‘
* });
*
* // an example using an object instead of an array
* let tasks = {
* one: function(callback) {
* setTimeout(function() {
* callback(null, ‘one‘);
* }, 200);
* },
* two: function(callback) {
* callback(‘two‘);
* },
* three: function(callback) {
* setTimeout(function() {
* callback(null, ‘three‘);
* }, 100);
* }
* };
*
* async.parallel(async.reflectAll(tasks),
* // optional callback
* function(err, results) {
* // values
* // results.one.value = ‘one‘
* // results.two.error = ‘two‘
* // results.three.value = ‘three‘
* });
*/
function reflectAll(tasks) {
var results;
if (isArray(tasks)) {
results = arrayMap(tasks, reflect);
} else {
results = {};
baseForOwn(tasks, function(task, key) {
results[key] = reflect.call(this, task);
});
}
return results;
}
/**
* The same as [`reject`]{@link module:Collections.reject} but runs a maximum of `limit` async operations at a
* time.
*
* @name rejectLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.reject]{@link module:Collections.reject}
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {Function} iteratee - An async truth test to apply to each item in
* `coll`.
* The should complete with a boolean value as its `result`.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Invoked with (err, results).
*/
var rejectLimit = doParallelLimit(reject$1);
/**
* The same as [`reject`]{@link module:Collections.reject} but runs only a single async operation at a time.
*
* @name rejectSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.reject]{@link module:Collections.reject}
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {Function} iteratee - An async truth test to apply to each item in
* `coll`.
* The should complete with a boolean value as its `result`.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Invoked with (err, results).
*/
var rejectSeries = doLimit(rejectLimit, 1);
/**
* Creates a function that returns `value`.
*
* @static
* @memberOf _
* @since 2.4.0
* @category Util
* @param {*} value The value to return from the new function.
* @returns {Function} Returns the new constant function.
* @example
*
* var objects = _.times(2, _.constant({ ‘a‘: 1 }));
*
* console.log(objects);
* // => [{ ‘a‘: 1 }, { ‘a‘: 1 }]
*
* console.log(objects[0] === objects[1]);
* // => true
*/
function constant$1(value) {
return function() {
return value;
};
}
/**
* Attempts to get a successful response from `task` no more than `times` times
* before returning an error. If the task is successful, the `callback` will be
* passed the result of the successful task. If all attempts fail, the callback
* will be passed the error and result (if any) of the final attempt.
*
* @name retry
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @see [async.retryable]{@link module:ControlFlow.retryable}
* @param {Object|number} [opts = {times: 5, interval: 0}| 5] - Can be either an
* object with `times` and `interval` or a number.
* * `times` - The number of attempts to make before giving up. The default
* is `5`.
* * `interval` - The time to wait between retries, in milliseconds. The
* default is `0`. The interval may also be specified as a function of the
* retry count (see example).
* * `errorFilter` - An optional synchronous function that is invoked on
* erroneous result. If it returns `true` the retry attempts will continue;
* if the function returns `false` the retry flow is aborted with the current
* attempt‘s error and result being returned to the final callback.
* Invoked with (err).
* * If `opts` is a number, the number specifies the number of times to retry,
* with the default interval of `0`.
* @param {AsyncFunction} task - An async function to retry.
* Invoked with (callback).
* @param {Function} [callback] - An optional callback which is called when the
* task has succeeded, or after the final failed attempt. It receives the `err`
* and `result` arguments of the last attempt at completing the `task`. Invoked
* with (err, results).
*
* @example
*
* // The `retry` function can be used as a stand-alone control flow by passing
* // a callback, as shown below:
*
* // try calling apiMethod 3 times
* async.retry(3, apiMethod, function(err, result) {
* // do something with the result
* });
*
* // try calling apiMethod 3 times, waiting 200 ms between each retry
* async.retry({times: 3, interval: 200}, apiMethod, function(err, result) {
* // do something with the result
* });
*
* // try calling apiMethod 10 times with exponential backoff
* // (i.e. intervals of 100, 200, 400, 800, 1600, ... milliseconds)
* async.retry({
* times: 10,
* interval: function(retryCount) {
* return 50 * Math.pow(2, retryCount);
* }
* }, apiMethod, function(err, result) {
* // do something with the result
* });
*
* // try calling apiMethod the default 5 times no delay between each retry
* async.retry(apiMethod, function(err, result) {
* // do something with the result
* });
*
* // try calling apiMethod only when error condition satisfies, all other
* // errors will abort the retry control flow and return to final callback
* async.retry({
* errorFilter: function(err) {
* return err.message === ‘Temporary error‘; // only retry on a specific error
* }
* }, apiMethod, function(err, result) {
* // do something with the result
* });
*
* // It can also be embedded within other control flow functions to retry
* // individual methods that are not as reliable, like this:
* async.auto({
* users: api.getUsers.bind(api),
* payments: async.retryable(3, api.getPayments.bind(api))
* }, function(err, results) {
* // do something with the results
* });
*
*/
function retry(opts, task, callback) {
var DEFAULT_TIMES = 5;
var DEFAULT_INTERVAL = 0;
var options = {
times: DEFAULT_TIMES,
intervalFunc: constant$1(DEFAULT_INTERVAL)
};
function parseTimes(acc, t) {
if (typeof t === ‘object‘) {
acc.times = +t.times || DEFAULT_TIMES;
acc.intervalFunc = typeof t.interval === ‘function‘ ?
t.interval :
constant$1(+t.interval || DEFAULT_INTERVAL);
acc.errorFilter = t.errorFilter;
} else if (typeof t === ‘number‘ || typeof t === ‘string‘) {
acc.times = +t || DEFAULT_TIMES;
} else {
throw new Error("Invalid arguments for async.retry");
}
}
if (arguments.length < 3 && typeof opts === ‘function‘) {
callback = task || noop;
task = opts;
} else {
parseTimes(options, opts);
callback = callback || noop;
}
if (typeof task !== ‘function‘) {
throw new Error("Invalid arguments for async.retry");
}
var _task = wrapAsync(task);
var attempt = 1;
function retryAttempt() {
_task(function(err) {
if (err && attempt++ < options.times &&
(typeof options.errorFilter != ‘function‘ ||
options.errorFilter(err))) {
setTimeout(retryAttempt, options.intervalFunc(attempt));
} else {
callback.apply(null, arguments);
}
});
}
retryAttempt();
}
/**
* A close relative of [`retry`]{@link module:ControlFlow.retry}. This method
* wraps a task and makes it retryable, rather than immediately calling it
* with retries.
*
* @name retryable
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.retry]{@link module:ControlFlow.retry}
* @category Control Flow
* @param {Object|number} [opts = {times: 5, interval: 0}| 5] - optional
* options, exactly the same as from `retry`
* @param {AsyncFunction} task - the asynchronous function to wrap.
* This function will be passed any arguments passed to the returned wrapper.
* Invoked with (...args, callback).
* @returns {AsyncFunction} The wrapped function, which when invoked, will
* retry on an error, based on the parameters specified in `opts`.
* This function will accept the same parameters as `task`.
* @example
*
* async.auto({
* dep1: async.retryable(3, getFromFlakyService),
* process: ["dep1", async.retryable(3, function (results, cb) {
* maybeProcessData(results.dep1, cb);
* })]
* }, callback);
*/
var retryable = function (opts, task) {
if (!task) {
task = opts;
opts = null;
}
var _task = wrapAsync(task);
return initialParams(function (args, callback) {
function taskFn(cb) {
_task.apply(null, args.concat(cb));
}
if (opts) retry(opts, taskFn, callback);
else retry(taskFn, callback);
});
};
/**
* Run the functions in the `tasks` collection in series, each one running once
* the previous function has completed. If any functions in the series pass an
* error to its callback, no more functions are run, and `callback` is
* immediately called with the value of the error. Otherwise, `callback`
* receives an array of results when `tasks` have completed.
*
* It is also possible to use an object instead of an array. Each property will
* be run as a function, and the results will be passed to the final `callback`
* as an object instead of an array. This can be a more readable way of handling
* results from {@link async.series}.
*
* **Note** that while many implementations preserve the order of object
* properties, the [ECMAScript Language Specification](http://www.ecma-international.org/ecma-262/5.1/#sec-8.6)
* explicitly states that
*
* > The mechanics and order of enumerating the properties is not specified.
*
* So if you rely on the order in which your series of functions are executed,
* and want this to work on all platforms, consider using an array.
*
* @name series
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Array|Iterable|Object} tasks - A collection containing
* [async functions]{@link AsyncFunction} to run in series.
* Each function can complete with any number of optional `result` values.
* @param {Function} [callback] - An optional callback to run once all the
* functions have completed. This function gets a results array (or object)
* containing all the result arguments passed to the `task` callbacks. Invoked
* with (err, result).
* @example
* async.series([
* function(callback) {
* // do some stuff ...
* callback(null, ‘one‘);
* },
* function(callback) {
* // do some more stuff ...
* callback(null, ‘two‘);
* }
* ],
* // optional callback
* function(err, results) {
* // results is now equal to [‘one‘, ‘two‘]
* });
*
* async.series({
* one: function(callback) {
* setTimeout(function() {
* callback(null, 1);
* }, 200);
* },
* two: function(callback){
* setTimeout(function() {
* callback(null, 2);
* }, 100);
* }
* }, function(err, results) {
* // results is now equal to: {one: 1, two: 2}
* });
*/
function series(tasks, callback) {
_parallel(eachOfSeries, tasks, callback);
}
/**
* Returns `true` if at least one element in the `coll` satisfies an async test.
* If any iteratee call returns `true`, the main `callback` is immediately
* called.
*
* @name some
* @static
* @memberOf module:Collections
* @method
* @alias any
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async truth test to apply to each item
* in the collections in parallel.
* The iteratee should complete with a boolean `result` value.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called as soon as any
* iteratee returns `true`, or after all the iteratee functions have finished.
* Result will be either `true` or `false` depending on the values of the async
* tests. Invoked with (err, result).
* @example
*
* async.some([‘file1‘,‘file2‘,‘file3‘], function(filePath, callback) {
* fs.access(filePath, function(err) {
* callback(null, !err)
* });
* }, function(err, result) {
* // if result is true then at least one of the files exists
* });
*/
var some = doParallel(_createTester(Boolean, identity));
/**
* The same as [`some`]{@link module:Collections.some} but runs a maximum of `limit` async operations at a time.
*
* @name someLimit
* @static
* @memberOf module:Collections
* @method
* @see [async.some]{@link module:Collections.some}
* @alias anyLimit
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - An async truth test to apply to each item
* in the collections in parallel.
* The iteratee should complete with a boolean `result` value.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called as soon as any
* iteratee returns `true`, or after all the iteratee functions have finished.
* Result will be either `true` or `false` depending on the values of the async
* tests. Invoked with (err, result).
*/
var someLimit = doParallelLimit(_createTester(Boolean, identity));
/**
* The same as [`some`]{@link module:Collections.some} but runs only a single async operation at a time.
*
* @name someSeries
* @static
* @memberOf module:Collections
* @method
* @see [async.some]{@link module:Collections.some}
* @alias anySeries
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async truth test to apply to each item
* in the collections in series.
* The iteratee should complete with a boolean `result` value.
* Invoked with (item, callback).
* @param {Function} [callback] - A callback which is called as soon as any
* iteratee returns `true`, or after all the iteratee functions have finished.
* Result will be either `true` or `false` depending on the values of the async
* tests. Invoked with (err, result).
*/
var someSeries = doLimit(someLimit, 1);
/**
* Sorts a list by the results of running each `coll` value through an async
* `iteratee`.
*
* @name sortBy
* @static
* @memberOf module:Collections
* @method
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async function to apply to each item in
* `coll`.
* The iteratee should complete with a value to use as the sort criteria as
* its `result`.
* Invoked with (item, callback).
* @param {Function} callback - A callback which is called after all the
* `iteratee` functions have finished, or an error occurs. Results is the items
* from the original `coll` sorted by the values returned by the `iteratee`
* calls. Invoked with (err, results).
* @example
*
* async.sortBy([‘file1‘,‘file2‘,‘file3‘], function(file, callback) {
* fs.stat(file, function(err, stats) {
* callback(err, stats.mtime);
* });
* }, function(err, results) {
* // results is now the original array of files sorted by
* // modified date
* });
*
* // By modifying the callback parameter the
* // sorting order can be influenced:
*
* // ascending order
* async.sortBy([1,9,3,5], function(x, callback) {
* callback(null, x);
* }, function(err,result) {
* // result callback
* });
*
* // descending order
* async.sortBy([1,9,3,5], function(x, callback) {
* callback(null, x*-1); //<- x*-1 instead of x, turns the order around
* }, function(err,result) {
* // result callback
* });
*/
function sortBy (coll, iteratee, callback) {
var _iteratee = wrapAsync(iteratee);
map(coll, function (x, callback) {
_iteratee(x, function (err, criteria) {
if (err) return callback(err);
callback(null, {value: x, criteria: criteria});
});
}, function (err, results) {
if (err) return callback(err);
callback(null, arrayMap(results.sort(comparator), baseProperty(‘value‘)));
});
function comparator(left, right) {
var a = left.criteria, b = right.criteria;
return a < b ? -1 : a > b ? 1 : 0;
}
}
/**
* Sets a time limit on an asynchronous function. If the function does not call
* its callback within the specified milliseconds, it will be called with a
* timeout error. The code property for the error object will be `‘ETIMEDOUT‘`.
*
* @name timeout
* @static
* @memberOf module:Utils
* @method
* @category Util
* @param {AsyncFunction} asyncFn - The async function to limit in time.
* @param {number} milliseconds - The specified time limit.
* @param {*} [info] - Any variable you want attached (`string`, `object`, etc)
* to timeout Error for more information..
* @returns {AsyncFunction} Returns a wrapped function that can be used with any
* of the control flow functions.
* Invoke this function with the same parameters as you would `asyncFunc`.
* @example
*
* function myFunction(foo, callback) {
* doAsyncTask(foo, function(err, data) {
* // handle errors
* if (err) return callback(err);
*
* // do some stuff ...
*
* // return processed data
* return callback(null, data);
* });
* }
*
* var wrapped = async.timeout(myFunction, 1000);
*
* // call `wrapped` as you would `myFunction`
* wrapped({ bar: ‘bar‘ }, function(err, data) {
* // if `myFunction` takes < 1000 ms to execute, `err`
* // and `data` will have their expected values
*
* // else `err` will be an Error with the code ‘ETIMEDOUT‘
* });
*/
function timeout(asyncFn, milliseconds, info) {
var fn = wrapAsync(asyncFn);
return initialParams(function (args, callback) {
var timedOut = false;
var timer;
function timeoutCallback() {
var name = asyncFn.name || ‘anonymous‘;
var error = new Error(‘Callback function "‘ + name + ‘" timed out.‘);
error.code = ‘ETIMEDOUT‘;
if (info) {
error.info = info;
}
timedOut = true;
callback(error);
}
args.push(function () {
if (!timedOut) {
callback.apply(null, arguments);
clearTimeout(timer);
}
});
// setup timer and call original function
timer = setTimeout(timeoutCallback, milliseconds);
fn.apply(null, args);
});
}
/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeCeil = Math.ceil;
var nativeMax = Math.max;
/**
* The base implementation of `_.range` and `_.rangeRight` which doesn‘t
* coerce arguments.
*
* @private
* @param {number} start The start of the range.
* @param {number} end The end of the range.
* @param {number} step The value to increment or decrement by.
* @param {boolean} [fromRight] Specify iterating from right to left.
* @returns {Array} Returns the range of numbers.
*/
function baseRange(start, end, step, fromRight) {
var index = -1,
length = nativeMax(nativeCeil((end - start) / (step || 1)), 0),
result = Array(length);
while (length--) {
result[fromRight ? length : ++index] = start;
start += step;
}
return result;
}
/**
* The same as [times]{@link module:ControlFlow.times} but runs a maximum of `limit` async operations at a
* time.
*
* @name timesLimit
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.times]{@link module:ControlFlow.times}
* @category Control Flow
* @param {number} count - The number of times to run the function.
* @param {number} limit - The maximum number of async operations at a time.
* @param {AsyncFunction} iteratee - The async function to call `n` times.
* Invoked with the iteration index and a callback: (n, next).
* @param {Function} callback - see [async.map]{@link module:Collections.map}.
*/
function timeLimit(count, limit, iteratee, callback) {
var _iteratee = wrapAsync(iteratee);
mapLimit(baseRange(0, count, 1), limit, _iteratee, callback);
}
/**
* Calls the `iteratee` function `n` times, and accumulates results in the same
* manner you would use with [map]{@link module:Collections.map}.
*
* @name times
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.map]{@link module:Collections.map}
* @category Control Flow
* @param {number} n - The number of times to run the function.
* @param {AsyncFunction} iteratee - The async function to call `n` times.
* Invoked with the iteration index and a callback: (n, next).
* @param {Function} callback - see {@link module:Collections.map}.
* @example
*
* // Pretend this is some complicated async factory
* var createUser = function(id, callback) {
* callback(null, {
* id: ‘user‘ + id
* });
* };
*
* // generate 5 users
* async.times(5, function(n, next) {
* createUser(n, function(err, user) {
* next(err, user);
* });
* }, function(err, users) {
* // we should now have 5 users
* });
*/
var times = doLimit(timeLimit, Infinity);
/**
* The same as [times]{@link module:ControlFlow.times} but runs only a single async operation at a time.
*
* @name timesSeries
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.times]{@link module:ControlFlow.times}
* @category Control Flow
* @param {number} n - The number of times to run the function.
* @param {AsyncFunction} iteratee - The async function to call `n` times.
* Invoked with the iteration index and a callback: (n, next).
* @param {Function} callback - see {@link module:Collections.map}.
*/
var timesSeries = doLimit(timeLimit, 1);
/**
* A relative of `reduce`. Takes an Object or Array, and iterates over each
* element in series, each step potentially mutating an `accumulator` value.
* The type of the accumulator defaults to the type of collection passed in.
*
* @name transform
* @static
* @memberOf module:Collections
* @method
* @category Collection
* @param {Array|Iterable|Object} coll - A collection to iterate over.
* @param {*} [accumulator] - The initial state of the transform. If omitted,
* it will default to an empty Object or Array, depending on the type of `coll`
* @param {AsyncFunction} iteratee - A function applied to each item in the
* collection that potentially modifies the accumulator.
* Invoked with (accumulator, item, key, callback).
* @param {Function} [callback] - A callback which is called after all the
* `iteratee` functions have finished. Result is the transformed accumulator.
* Invoked with (err, result).
* @example
*
* async.transform([1,2,3], function(acc, item, index, callback) {
* // pointless async:
* process.nextTick(function() {
* acc.push(item * 2)
* callback(null)
* });
* }, function(err, result) {
* // result is now equal to [2, 4, 6]
* });
*
* @example
*
* async.transform({a: 1, b: 2, c: 3}, function (obj, val, key, callback) {
* setImmediate(function () {
* obj[key] = val * 2;
* callback();
* })
* }, function (err, result) {
* // result is equal to {a: 2, b: 4, c: 6}
* })
*/
function transform (coll, accumulator, iteratee, callback) {
if (arguments.length <= 3) {
callback = iteratee;
iteratee = accumulator;
accumulator = isArray(coll) ? [] : {};
}
callback = once(callback || noop);
var _iteratee = wrapAsync(iteratee);
eachOf(coll, function(v, k, cb) {
_iteratee(accumulator, v, k, cb);
}, function(err) {
callback(err, accumulator);
});
}
/**
* It runs each task in series but stops whenever any of the functions were
* successful. If one of the tasks were successful, the `callback` will be
* passed the result of the successful task. If all tasks fail, the callback
* will be passed the error and result (if any) of the final attempt.
*
* @name tryEach
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Array|Iterable|Object} tasks - A collection containing functions to
* run, each function is passed a `callback(err, result)` it must call on
* completion with an error `err` (which can be `null`) and an optional `result`
* value.
* @param {Function} [callback] - An optional callback which is called when one
* of the tasks has succeeded, or all have failed. It receives the `err` and
* `result` arguments of the last attempt at completing the `task`. Invoked with
* (err, results).
* @example
* async.try([
* function getDataFromFirstWebsite(callback) {
* // Try getting the data from the first website
* callback(err, data);
* },
* function getDataFromSecondWebsite(callback) {
* // First website failed,
* // Try getting the data from the backup website
* callback(err, data);
* }
* ],
* // optional callback
* function(err, results) {
* Now do something with the data.
* });
*
*/
function tryEach(tasks, callback) {
var error = null;
var result;
callback = callback || noop;
eachSeries(tasks, function(task, callback) {
wrapAsync(task)(function (err, res/*, ...args*/) {
if (arguments.length > 2) {
result = slice(arguments, 1);
} else {
result = res;
}
error = err;
callback(!err);
});
}, function () {
callback(error, result);
});
}
/**
* Undoes a [memoize]{@link module:Utils.memoize}d function, reverting it to the original,
* unmemoized form. Handy for testing.
*
* @name unmemoize
* @static
* @memberOf module:Utils
* @method
* @see [async.memoize]{@link module:Utils.memoize}
* @category Util
* @param {AsyncFunction} fn - the memoized function
* @returns {AsyncFunction} a function that calls the original unmemoized function
*/
function unmemoize(fn) {
return function () {
return (fn.unmemoized || fn).apply(null, arguments);
};
}
/**
* Repeatedly call `iteratee`, while `test` returns `true`. Calls `callback` when
* stopped, or an error occurs.
*
* @name whilst
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Function} test - synchronous truth test to perform before each
* execution of `iteratee`. Invoked with ().
* @param {AsyncFunction} iteratee - An async function which is called each time
* `test` passes. Invoked with (callback).
* @param {Function} [callback] - A callback which is called after the test
* function has failed and repeated execution of `iteratee` has stopped. `callback`
* will be passed an error and any arguments passed to the final `iteratee`‘s
* callback. Invoked with (err, [results]);
* @returns undefined
* @example
*
* var count = 0;
* async.whilst(
* function() { return count < 5; },
* function(callback) {
* count++;
* setTimeout(function() {
* callback(null, count);
* }, 1000);
* },
* function (err, n) {
* // 5 seconds have passed, n = 5
* }
* );
*/
function whilst(test, iteratee, callback) {
callback = onlyOnce(callback || noop);
var _iteratee = wrapAsync(iteratee);
if (!test()) return callback(null);
var next = function(err/*, ...args*/) {
if (err) return callback(err);
if (test()) return _iteratee(next);
var args = slice(arguments, 1);
callback.apply(null, [null].concat(args));
};
_iteratee(next);
}
/**
* Repeatedly call `iteratee` until `test` returns `true`. Calls `callback` when
* stopped, or an error occurs. `callback` will be passed an error and any
* arguments passed to the final `iteratee`‘s callback.
*
* The inverse of [whilst]{@link module:ControlFlow.whilst}.
*
* @name until
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.whilst]{@link module:ControlFlow.whilst}
* @category Control Flow
* @param {Function} test - synchronous truth test to perform before each
* execution of `iteratee`. Invoked with ().
* @param {AsyncFunction} iteratee - An async function which is called each time
* `test` fails. Invoked with (callback).
* @param {Function} [callback] - A callback which is called after the test
* function has passed and repeated execution of `iteratee` has stopped. `callback`
* will be passed an error and any arguments passed to the final `iteratee`‘s
* callback. Invoked with (err, [results]);
*/
function until(test, iteratee, callback) {
whilst(function() {
return !test.apply(this, arguments);
}, iteratee, callback);
}
/**
* Runs the `tasks` array of functions in series, each passing their results to
* the next in the array. However, if any of the `tasks` pass an error to their
* own callback, the next function is not executed, and the main `callback` is
* immediately called with the error.
*
* 连续执行数组中的函数,每次通过数组下一个函数的结果。
* 然而,数组任务中的任意一个函数结果传递失败,那么该函数的下一个函数将不会执行,
* 并且主回调函数立马把错误作为参数执行。
*
*
* @name waterfall
* @static
* @memberOf module:ControlFlow
* @method
* @category Control Flow
* @param {Array} tasks - An array of [async functions]{@link AsyncFunction}
* to run.
* Each function should complete with any number of `result` values.
* The `result` values will be passed as arguments, in order, to the next task.
* @param {Function} [callback] - An optional callback to run once all the
* functions have completed. This will be passed the results of the last task‘s
* callback. Invoked with (err, [results]).
* @returns undefined
* @example
*
* async.waterfall([
* function(callback) {
* callback(null, ‘one‘, ‘two‘);
* },
* function(arg1, arg2, callback) {
* // arg1 now equals ‘one‘ and arg2 now equals ‘two‘
* callback(null, ‘three‘);
* },
* function(arg1, callback) {
* // arg1 now equals ‘three‘
* callback(null, ‘done‘);
* }
* ], function (err, result) {
* // result now equals ‘done‘
* });
*
* // Or, with named functions:
* async.waterfall([
* myFirstFunction,
* mySecondFunction,
* myLastFunction,
* ], function (err, result) {
* // result now equals ‘done‘
* });
* function myFirstFunction(callback) {
* callback(null, ‘one‘, ‘two‘);
* }
* function mySecondFunction(arg1, arg2, callback) {
* // arg1 now equals ‘one‘ and arg2 now equals ‘two‘
* callback(null, ‘three‘);
* }
* function myLastFunction(arg1, callback) {
* // arg1 now equals ‘three‘
* callback(null, ‘done‘);
* }
*/
var waterfall = function(tasks, callback) { // tasks: 异步函数数组容器, callback: 回调
callback = once(callback || noop); // 回调函数
if (!isArray(tasks)) return callback(new Error(‘First argument to waterfall must be an array of functions‘)); // 第一个参数必须是数组(函数数组)!
if (!tasks.length) return callback(); // 空数组的话直接调用回调函数(无参数)
var taskIndex = 0; // 任务索引
function nextTask(args) { // 参数数组
var task = wrapAsync(tasks[taskIndex++]); // 数组中的任务
args.push(onlyOnce(next)); // 把next方法添加到args数组中去
task.apply(null, args); // 调用数组中task函数(参数是数组)
};
function next(err/*, ...args*/) { // 其实就是函数参数中的回调函数callback
if (err || taskIndex === tasks.length) { // 只要有错误或者函数数组任务都完成了
return callback.apply(null, arguments); // 就执行回调
};
nextTask(slice(arguments, 1)); // 数组中的函数没循环完且没出错,那就继续调用
};
nextTask([]); // 调用
};
/**
* An "async function" in the context of Async is an asynchronous function with
* a variable number of parameters, with the final parameter being a callback.
* (`function (arg1, arg2, ..., callback) {}`)
* The final callback is of the form `callback(err, results...)`, which must be
* called once the function is completed. The callback should be called with a
* Error as its first argument to signal that an error occurred.
* Otherwise, if no error occurred, it should be called with `null` as the first
* argument, and any additional `result` arguments that may apply, to signal
* successful completion.
* The callback must be called exactly once, ideally on a later tick of the
* JavaScript event loop.
*
* This type of function is also referred to as a "Node-style async function",
* or a "continuation passing-style function" (CPS). Most of the methods of this
* library are themselves CPS/Node-style async functions, or functions that
* return CPS/Node-style async functions.
*
* Wherever we accept a Node-style async function, we also directly accept an
* [ES2017 `async` function]{@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function}.
* In this case, the `async` function will not be passed a final callback
* argument, and any thrown error will be used as the `err` argument of the
* implicit callback, and the return value will be used as the `result` value.
* (i.e. a `rejected` of the returned Promise becomes the `err` callback
* argument, and a `resolved` value becomes the `result`.)
*
* Note, due to JavaScript limitations, we can only detect native `async`
* functions and not transpilied implementations.
* Your environment must have `async`/`await` support for this to work.
* (e.g. Node > v7.6, or a recent version of a modern browser).
* If you are using `async` functions through a transpiler (e.g. Babel), you
* must still wrap the function with [asyncify]{@link module:Utils.asyncify},
* because the `async function` will be compiled to an ordinary function that
* returns a promise.
*
* @typedef {Function} AsyncFunction
* @static
*/
/**
* Async is a utility module which provides straight-forward, powerful functions
* for working with asynchronous JavaScript. Although originally designed for
* use with [Node.js](http://nodejs.org) and installable via
* `npm install --save async`, it can also be used directly in the browser.
* @module async
* @see AsyncFunction
*/
/**
* A collection of `async` functions for manipulating collections, such as
* arrays and objects.
* @module Collections
*/
/**
* A collection of `async` functions for controlling the flow through a script.
* @module ControlFlow
*/
/**
* A collection of `async` utility functions.
* @module Utils
*/
var index = {
applyEach: applyEach,
applyEachSeries: applyEachSeries,
apply: apply,
asyncify: asyncify,
auto: auto,
autoInject: autoInject,
cargo: cargo,
compose: compose,
concat: concat,
concatSeries: concatSeries,
constant: constant,
detect: detect,
detectLimit: detectLimit,
detectSeries: detectSeries,
dir: dir,
doDuring: doDuring,
doUntil: doUntil,
doWhilst: doWhilst,
during: during,
each: eachLimit,
eachLimit: eachLimit$1,
eachOf: eachOf,
eachOfLimit: eachOfLimit,
eachOfSeries: eachOfSeries,
eachSeries: eachSeries,
ensureAsync: ensureAsync,
every: every,
everyLimit: everyLimit,
everySeries: everySeries,
filter: filter,
filterLimit: filterLimit,
filterSeries: filterSeries,
forever: forever,
groupBy: groupBy,
groupByLimit: groupByLimit,
groupBySeries: groupBySeries,
log: log,
map: map,
mapLimit: mapLimit,
mapSeries: mapSeries,
mapValues: mapValues,
mapValuesLimit: mapValuesLimit,
mapValuesSeries: mapValuesSeries,
memoize: memoize,
nextTick: nextTick,
parallel: parallelLimit,
parallelLimit: parallelLimit$1,
priorityQueue: priorityQueue,
queue: queue$1,
race: race,
reduce: reduce,
reduceRight: reduceRight,
reflect: reflect,
reflectAll: reflectAll,
reject: reject,
rejectLimit: rejectLimit,
rejectSeries: rejectSeries,
retry: retry,
retryable: retryable,
seq: seq,
series: series,
setImmediate: setImmediate$1,
some: some,
someLimit: someLimit,
someSeries: someSeries,
sortBy: sortBy,
timeout: timeout,
times: times,
timesLimit: timeLimit,
timesSeries: timesSeries,
transform: transform,
tryEach: tryEach,
unmemoize: unmemoize,
until: until,
waterfall: waterfall,
whilst: whilst,
// aliases
all: every,
any: some,
forEach: eachLimit,
forEachSeries: eachSeries,
forEachLimit: eachLimit$1,
forEachOf: eachOf,
forEachOfSeries: eachOfSeries,
forEachOfLimit: eachOfLimit,
inject: reduce,
foldl: reduce,
foldr: reduceRight,
select: filter,
selectLimit: filterLimit,
selectSeries: filterSeries,
wrapSync: asyncify
};
exports[‘default‘] = index;
exports.applyEach = applyEach;
exports.applyEachSeries = applyEachSeries;
exports.apply = apply;
exports.asyncify = asyncify;
exports.auto = auto;
exports.autoInject = autoInject;
exports.cargo = cargo;
exports.compose = compose;
exports.concat = concat;
exports.concatSeries = concatSeries;
exports.constant = constant;
exports.detect = detect;
exports.detectLimit = detectLimit;
exports.detectSeries = detectSeries;
exports.dir = dir;
exports.doDuring = doDuring;
exports.doUntil = doUntil;
exports.doWhilst = doWhilst;
exports.during = during;
exports.each = eachLimit;
exports.eachLimit = eachLimit$1;
exports.eachOf = eachOf;
exports.eachOfLimit = eachOfLimit;
exports.eachOfSeries = eachOfSeries;
exports.eachSeries = eachSeries;
exports.ensureAsync = ensureAsync;
exports.every = every;
exports.everyLimit = everyLimit;
exports.everySeries = everySeries;
exports.filter = filter;
exports.filterLimit = filterLimit;
exports.filterSeries = filterSeries;
exports.forever = forever;
exports.groupBy = groupBy;
exports.groupByLimit = groupByLimit;
exports.groupBySeries = groupBySeries;
exports.log = log;
exports.map = map;
exports.mapLimit = mapLimit;
exports.mapSeries = mapSeries;
exports.mapValues = mapValues;
exports.mapValuesLimit = mapValuesLimit;
exports.mapValuesSeries = mapValuesSeries;
exports.memoize = memoize;
exports.nextTick = nextTick;
exports.parallel = parallelLimit;
exports.parallelLimit = parallelLimit$1;
exports.priorityQueue = priorityQueue;
exports.queue = queue$1;
exports.race = race;
exports.reduce = reduce;
exports.reduceRight = reduceRight;
exports.reflect = reflect;
exports.reflectAll = reflectAll;
exports.reject = reject;
exports.rejectLimit = rejectLimit;
exports.rejectSeries = rejectSeries;
exports.retry = retry;
exports.retryable = retryable;
exports.seq = seq;
exports.series = series;
exports.setImmediate = setImmediate$1;
exports.some = some;
exports.someLimit = someLimit;
exports.someSeries = someSeries;
exports.sortBy = sortBy;
exports.timeout = timeout;
exports.times = times;
exports.timesLimit = timeLimit;
exports.timesSeries = timesSeries;
exports.transform = transform;
exports.tryEach = tryEach;
exports.unmemoize = unmemoize;
exports.until = until;
exports.waterfall = waterfall;
exports.whilst = whilst;
exports.all = every;
exports.allLimit = everyLimit;
exports.allSeries = everySeries;
exports.any = some;
exports.anyLimit = someLimit;
exports.anySeries = someSeries;
exports.find = detect;
exports.findLimit = detectLimit;
exports.findSeries = detectSeries;
exports.forEach = eachLimit;
exports.forEachSeries = eachSeries;
exports.forEachLimit = eachLimit$1;
exports.forEachOf = eachOf;
exports.forEachOfSeries = eachOfSeries;
exports.forEachOfLimit = eachOfLimit;
exports.inject = reduce;
exports.foldl = reduce;
exports.foldr = reduceRight;
exports.select = filter;
exports.selectLimit = filterLimit;
exports.selectSeries = filterSeries;
exports.wrapSync = asyncify;
Object.defineProperty(exports, ‘__esModule‘, { value: true });
})));
时间： 2024-11-09 01:25:10