ES6-string, numeric, boolean and function parameter destructuring assignment

ES6-string, numeric, boolean and function parameter destructuring assignment

1. Deconstruction and assignment of strings The
   reason why a string can be deconstructed is because the string is converted into an array-like object

        let [a, b, c, d, e] = 'Jisoo';
        console.log(a); //J
        console.log(b); //i
        console.log(c); //s
        console.log(d); //o
        console.log(e); //o

The class array has a length attribute, so this attribute can also be deconstructed and assigned

        let {
            length: len
        } = 'jisoo';
        console.log(len);//5

2. Destructuring assignment of numeric and boolean values
   If the right side of the equal sign is numeric or boolean, it will be converted to an object first

        let {
            prop: x
        } = 123;
        console.log(x); //undefined(123被转换为对象)
        let {
            prop1: y
        } = true;
        console.log(y); //undefined(true被转换为对象)
        let {
            prop2: z
        } = undefined;//undefined不能转换为对象，所以报错
        console.log(z); //Error

3. Destructuring assignment of function parameters

        function add([x, y]) {
            return x + y;
        }
        var sum = add([1, 2]);
        console.log(sum);

The function add() parameter surface is an array, but in fact, at the moment when the parameter is passed in, the array parameter is deconstructed into the variable x and y
. The deconstruction of the function parameter can also use the default value

        function move({
            x = 0,
            y = 0
        } = {}) {
            return [x, y];
        }
        var x = move({
            x: 3,
            y: 8
        });
        console.log(x); //[3,8]
        var y = move({
            x: 3
        });
        console.log(y); //[3,0]
        var z = move({}); //
        console.log(z); //[0,0]