jquery的each方法简单实现

jquery的each方法实现(带循环终止功能)

    ~function () {
        function each(callback) {
            if (!callback) return;
            for (let i = 0; i < this.length; i++) {
                let flag = callback(this[i], i);
                if (flag === false) break;
            }
        }
        function each1(arr, callback) {
            if (!Array.isArray(arr) || !callback) return;
            for (let i = 0; i < arr.length; i++) {
                let flag = callback.call(arr, arr[i], i);
                if (flag === false) break;
            }
        }
        ['each', 'each1'].forEach(item => {
            Array.prototype[item] = eval(item);
        })


    }();
    [1, 2, 3, 4].each((item, index) => {
        console.log(item);
        if (index >= 1) return false;
    })
    Array.prototype.each1([5,6,7],(item, index) => {
        console.log(item);
        if (index >= 1) return false;
    })