Object.keys(obj)
总结一下就是:
obj为
- 对象,返回属性名
- 字符串,返回索引
- 数组,返回索引
例子为:
传入对象,返回属性名
var obj = {'a':'123','b':'345'};
console.log(Object.keys(obj)); //['a','b']
var obj1 = { 100: "a", 2: "b", 7: "c"};
console.log(Object.keys(obj1)); // console: ["2", "7", "100"]
var obj2 = Object.create({}, { getFoo : { value : function () { return this.foo } } });
obj2.foo = 1;
console.log(Object.keys(obj2)); // console: ["foo"]
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传入字符串,返回索引
var str = 'ab1234';
console.log(Object.keys(obj)); //[0,1,2,3,4,5]
---------------------
数组 返回索引
var arr = ["a", "b", "c"];
console.log(Object.keys(arr)); // console: ["0", "1", "2"]