Array 判斷是不是arr
instanceof 操作符
let arr = [];
arr instanceof Array// true
constructor 構(gòu)造器
let arr = [];
arr.constructor === Array// true
isPrototypeOf Array原型鏈上
let arr = [];
Array.prototype.isPrototypeOf(arr) // ture
Object.getPrototypeOf
let arr = [];
Object.getPrototypeOf(arr) === Array.prototype // ture
Object.prototype.toString
let arr = [];
Object.prototype.toString.call(arr) === '[object Array]' // ture
Array.isArray
let arr = [];
Array.isArray(arr)
