1. es扩展运算符
扩展运算符将一个数组转为用逗号分隔的参数序列;
<script> console.log(...[1, 2, 3]) //1 2 3 // (1)将一个数组,变为参数序列 let add = (x, y) => x + y; let numbers = [1, 2]; console.log(add(...numbers))//3 // (2)使用扩展运算符展开数组代替apply方法,将数组转为函数的参数 // ES5 取数组最大值 console.log(Math.max.apply(this, [654, 233, 727])); //727 // ES6 扩展运算符 console.log(Math.max(...[654, 233, 727])) //727 // 相当于 console.log(Math.max(654, 233, 727))//727 // (3)使用push将一个数组添加到另一个数组的尾部 // ES5 写法 let arr1 = [1, 2, 3]; let arr2 = [4, 5, 6]; Array.prototype.push.apply(arr1, arr2); console.log(arr1) // [1, 2, 3, 4, 5, 6] // push方法的参数不能是数组,通过apply方法使用push方法 // ES6 写法 let arr3 = [1, 2, 3]; let arr4 = [4, 5, 6]; arr3.push(...arr4); console.log(arr3) // [1, 2, 3, 4, 5, 6] // (4)合并数组 let a = [‘a‘, ‘b‘]; let b = [‘c‘]; let c = [‘d‘, ‘e‘]; // ES5 的合并数组 let d = a.concat(b, c); console.log(d) //["a", "b", "c", "d", "e"] // ES6 的合并数组 let e = [...a, ...b, ...c] console.log(e) //["a", "b", "c", "d", "e"] // (6)将字符串转换为数组 let h = [...‘hello‘] console.log(h) //["h", "e", "l", "l", "o"] // ES5 let str = ‘world‘.split(‘‘) //["w", "o", "r", "l", "d"] console.log(str) // (6)转换伪数组为真数组 var nodeList = document.querySelectorAll(‘p‘); console.log(nodeList) var array = [...nodeList]; console.log(array) // 具有iterator接口的伪数组,非iterator对象用Array.from方法 // (7)map结构 let map = new Map([ [1, ‘one‘], [2, ‘two‘], [3, ‘three‘], ]); let arr = [...map.keys()]; console.log(arr) //[1, 2, 3] </script>
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原文地址:https://www.cnblogs.com/shiyun32/p/11182692.html
时间: 2024-10-10 09:11:32