js 判断值为Array or Object的方法

Posted 2020-10-18 狂奔的小马扎

①obj instanceof Array / Object

②Array.prototype.isPrototypeOf(obj)

③Object.prototype.toString.call(obj)

④Array.isArray(obj)

 

实例：

//typeof()  【原始类型：可分辨；引用类型：object】
console.log(typeof([]));  //object
console.log(typeof({}));  //object

//①obj instanceof 构造函数名/类型名
console.log([] instanceof Array);  //true
console.log({} instanceof Array);  //false

//②Array.prototype.isPrototypeof(obj)
console.log(Array.prototype.isPrototypeOf([]));  //true
console.log(Array.prototype.isPrototypeOf({}));  //false

//③Object.prototype.toString.call(obj)
console.log(Object.prototype.toString.call([]));  //[object Array]
console.log(Object.prototype.toString.call({}));  //[object Object]

//④ES5: Array.isArray(obj) 【兼容性】
console.log(Array.isArray([]));  //true
console.log(Array.isArray({}));  //false