• Object.keys(obj)返回参数obj可被枚举的属性
  • 标签 : 其他    来源 : 标签: object.keys js 分类: JS
  • Object.keys(obj),返回一个数组,数组里是该obj可被枚举的所有属性。请看示例:


    示例一:
        function Pasta(grain, width, shape) {
                this.grain = grain;
                this.width = width;
                this.shape = shape;
                this.toString = function () {
                        return (this.grain + ", " + this.width + ", " + this.shape);
                }
        }

        console.log(Object.keys(Pasta)); //console: []
        var spaghetti = new Pasta("wheat", 0.2, "circle");
        console.log(Object.keys(spaghetti)); //console: ["grain", "width", "shape", "toString"]


    示例二:

        var arr = ["a", "b", "c"];
        console.log(Object.keys(arr)); // console: ["0", "1", "2"]


        var obj = { 0 : "a", 1 : "b", 2 : "c"};
        console.log(Object.keys(obj)); // console: ["0", "1", "2"]


        var an_obj = { 100: "a", 2: "b", 7: "c"};
        console.log(Object.keys(an_obj)); // console: ["2", "7", "100"]


        var my_obj = Object.create({}, { getFoo : { value : function () { return this.foo } } });
        my_obj.foo = 1;

        console.log(Object.keys(my_obj)); // console: ["foo"]