打乱数组

    var a = [];
    for (var i = 0; i < 10; i++) {
        a.push(i)
    };
    a.map((x, y) => {
        var f = Math.floor(Math.random() * 10 );
        var t = a[y];
        a[y] = a[f];
        a[f] = t;
    })
    console.log(a);