JS中三个点(...)是什么鬼?
什么意思?
// 数组 var number = [1,2,3,4,5,6] console.log(...number) //1 2 3 4 5 6 //对象 var man = {name:'chuichui',height:176} console.log({...man}) / {name:'chuichui',height:176}
有什么用?
复制用它
//数组的复制 var arr1 = ['hello'] var arr2 =[...arr1] arr2 // ['hello'] //对象的复制 var obj1 = {name:'chuichui'} var obj2 ={...arr} ob12 // {name:'chuichui'}
合并用它
//数组的合并 var arr1 = ['hello'] var arr2 =['chuichui'] var mergeArr = [...arr1,...arr2] mergeArr // ['hello','chuichui'] // 对象分合并 var obj1 = {name:'chuichui'} var obj2 = {height:176} var mergeObj = {...obj1,...obj2} mergeObj // {name: "chuichui", height: 176}
字符转数组用它
var arr1 = [...'hello'] arr1 // ["h", "e", "l", "l", "o"]
函数传参用它
function f(v,w,x,y,z){ } var args = [2,3] f(1,...args,4,...[5])
当我们想把数组中的元素迭代为函数参数时,用它!
function f(x,y,z){} var args = [1,2,3] f(...args) // 以前的方法 f.apply(null,args);
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