SOURCE

Function.prototype.myCall = function (context = window, ...args) {
    if (this === Function.prototype) {
        return undefined; // 用于防止 Function.prototype.myCall() 直接调用
    }
    context = context || window;
    const fn = Symbol();
    context[fn] = this;
    const result = context[fn](...args);
    delete context[fn];
    return result;
}

const obj = {
    name: 'kalen',
    age: 18
}

function callMe() {
    console.log('===')
    console.log(this.name)
    console.log(arguments)
}

function callMe2() {
    console.log('------')
    console.log(this.age)
    console.log(arguments)
}

console.log('参考链接：https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Function/call')

callMe()

callMe.myCall(obj, 1, 2, 3)
callMe2.myCall(obj, 4, 5, 6)
callMe.call('call', 7, 8, 9)

// 函数调用函数，this.name会返回函数名