AngularJS Promise

先看两个官方文档

https://docs.angularjs.org/api/ng/service/$http

http://fdietz.github.io/recipes-with-angular-js/consuming-external-services/deferred-and-promise.html

首先呢  要知道$http和$.ajax一样   本身是可以直接链式的调用 .success .error 的(jQuery里面的ajax是failed)

那么为什么我还需要dfd呢  dfd更灵活，可以在很多地方使用  不仅仅局限于http请求

这里有个比较搓的例子 感受一下他们的区别

        var list = dataSource.makeHttpRequest(‘/list‘, ‘POST‘, {
                "xxx": xxx
            });
        list.httpRequest.success(function(data){
            console.log(data);
        });
        list.promise.then(function(data){
            console.log(data);
        });

dataSource是我定义的一个factory  返回的httpRequest就是$http.post   而Promise则是dfd.promise

    myApp.factory(‘dataSource‘, [‘$http‘, ‘$q‘, function($http, $q) {
        return {
            makeHttpRequest: function(url, method, params) {
                var httpRequest;
                var defer = $q.defer();

                if (method == ‘GET‘) {

                    //$http.get()
                } else if (method == ‘POST‘) {
                    httpRequest = $http.post(url, params);
                    httpRequest.success(function(data) {
                        if (data.status == 0) {
                            defer.resolve(data);
                        } else {
                            defer.reject(data);
                        }

                    }).error(function(msg) {
                        defer.reject(msg);
                    });
                }

                return {
                    promise: defer.promise,
                    httpRequest: httpRequest
                }
            }
        }
    }]);