实现forEach和map
# 实现forEach和map
//实现
Array.prototype.MyForEach = function (fn, context) {
context = context || window;
for (let i = 0; i < this.length; i++) {
fn.apply(context, [this[i], i, this]);
}
};
/**
* map用法
* 第一个参数是函数,第二个参数是this
*/
Array.prototype.MyMap = function (fn, context) {
context = context || window;
let res = [];
for (let i = 0; i < this.length; i++) {
res[i] = fn.call(context, this[i], i, this);
}
return res;
};
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