JavaScript的灵活应用

1、查找数组的最大值和最小值

(1)
Math.max.qpply(null,array);
Math.min.qpply(null,array);
(2)
eval("Math.max("+array.toString()+")")
eval("Math.min("+array.toString()+")")
(3)
ary.sort(function(a,b){
        return a-b;
})
(4)
let max=array[0],min=array[0];
for(let i=1;i<array.length;i++){
        let cur=array[i];
        max<cur?max=cur:null;
        min>cur?min=cur:null;
}

2.转化一个数字数组为function数组（每个function都弹出相应的数字）

var a = [111, 2, 6, 4, 22, 5, 99, 3];
a = a.map(function (value) {
    return function () {
        return value;
    }
});
console.log(a[2]());

3.给object数组进行排序（排序条件是每个元素对象的属性个数）

var b = [{a: 1, b: 2}, {a: 1, b: 2, c: 3, d: 5}, {a: 1}, {a: 1, b: 2, c: 3, d: 4}];
//拓展count方法
Object.prototype.count = (
    Object.prototype.hasOwnProperty('_count_') ?
        function () {
            return this._count_;
        } :
        function () {
            var p, count = 0;
            for (p in this) {
                if (this.hasOwnProperty(p)) {
                    count++;
                }
            }
            return count;
        }    );
function compare(obj1, obj2) {
    return obj1.count() - obj2.count();
}
console.log(b.sort(compare));

4.实现如下语法的功能：var a = add(2)(3)(4);怎么实现可以一直不停地累加呢？

function add(x) {
    var sum = x;
    var fn = function (y) {
        sum += y;

        return fn;
    };
    fn.valueOf = fn.toString = function () {
        return sum;
    };
    return fn;
}
console.log((add(2)(4)).toString());//6
console.log(add(2));//function 2
console.log(add(3)(8)(9));//function 20
console.log(add(3)(8)(9)(10));//function 30