如何判断变量是对象还是数组

1.instanceof

 

var arr = [1, 2, 3];

var obj = {

    name: 'mt',

    age: 6

}

console.log(arr instanceof Array); //true

console.log(obj instanceof Array); //false

 

2.constructor

 

var arr = [1, 2, 3];

var obj = {

    name: 'mt',

    age: 6

}

console.log(arr.constructor === Array); //true

console.log(obj.constructor === Array); //false

 

3.Object.prototype.toString()

 

var arr = [1, 2, 3];

var obj = {

    name: 'mt',

    age: 6

}

console.log(Object.prototype.toString.call(arr) === '[object Array]'); //true

console.log(Object.prototype.toString.call(boj) === '[object Array]'); //false

 

4.数组仅有的方法(如：sort,pop等)

 

var arr = [1, 2, 3];

var obj = {

    name: 'mt',
    age: 6

}

console.log(arr.sort === Array.prototype.sort); //true

console.log(obj.sort === Array.prototype.sort); //false