call

note

The call() method of Function instances call this function with a given this value and

arguments provided individually.

// 实现
Function.prototype.myCall = function (context, ...args) {
    context.fn = this; // 临时给当前对象context添加一个随意名字的函数fn并指定其逻辑为this
    context.fn(...args); // 执行刚刚添加的函数
    delete context.fn; // 用完就丢弃即可
}