js闭包用法以及和bind的结合使用

news2024/9/21 4:25:07

bind用法

        let info = { name: "xuhaitao", age: 36 }
        function haitao() {
            console.log(this);
        }

        let fun = haitao.bind(info)
        fun();
        haitao();

控制台打印:

闭包用法:

function xiaoMing() {
            let v = 1;
            function jia() {
                v++;
                console.log(v);
            }

            function getV() {
                console.log(v);
            }
            return { jia: jia, getV: getV }
}


let x01 = xiaoMing();
x01.jia();  //2
x01.jia();  //3
x01.jia();  //4
x01.getV(); //4
let x02 = xiaoMing();
x02.jia();  //2
x02.jia();  //3
x02.jia();  //4
x02.getV(); //4

通过下面是实验，发现两个：

1 返回的方法放入数组中，然后遍历执行数组中的方法，发现this变成了数组
2 闭包仍然存在

  <script type="text/javascript">

        function xiaoMing() {
            let aa = { name: "jia011", age: 3338 };
            function show() {
                console.log(aa.name, aa.age);
                console.log(this);
                printt();
            }
            function printt() {
                console.log(aa.name, aa.age);
            }
            return { show: show }
        }

        function xiaoHong() {
            let aa = { name: "jia022", age: 2223 };
            function show() {
                console.log(aa.name, aa.age);
                console.log(this);
                printt();
            }
            function printt() {
                console.log(aa.name, aa.age);
            }
            return { show: show }
        }


        let obj01 = xiaoMing();
        let obj02 = xiaoHong();

        console.log("++++++++++++++++++++++++++++++++++++++++++")

        var shuzu = [];//创建一个数组，用于保存各返回对象的方法
        shuzu.push(obj01.show);
        shuzu.push(obj02.show);

        for (var i = 0; i < shuzu.length; i++) {
            shuzu[i]();
            console.log("++++++++++++++++++++++++++++++++++++++++++")
        }
    </script>