Object.defineProperty

var obj = {    test: "hello"};obj['favor'] = 'orange';//对象已有的属性添加特性描述// Object.defineProperty(obj, "test", {//     configurable: true,//     enumerable: true,//     writable: true// });//对象新添加的属性的特性描述Object.defineProperty(obj, "age", {    configurable: true,    value: 22,    enumerable: true,    writable: false});obj['age'] = 10;console.log(obj);

检测类型Object.prototype.toString.call

Object.prototype.toString.call();Object.prototype.toString.call([]); //"[object Array]"Object.prototype.toString.call({}); //"[object Object]"Object.prototype.toString.call(null); //"[object Null]"Object.prototype.toString.call(undefined); //"[object Undefined]"

转数组

Array.prototype.slice().call(likeArr);

let likeArrToArr = function (likeArr) {    var arr = [];    try {        arr = Array.prototype.slice.call(likeArr);    } catch (e) {        for (var i = 0; i < likeArr.length; i++) {            arr[arr.length] = likeArr[i];        }    }    return arr;};var arr = {length: 2, 0: 'first', 1: 'second'};console.log(likeArrToArr(arr));var arr2 = [0,11,22,33];console.log(likeArrToArr(arr2));