如何使用50行javaScript代码实现简单版的call,apply,bind

function test() {
 console.log(this);
};

test();
指向window 输出下面的代码：
// Window {speechSynthesis: SpeechSynthesis, caches: CacheStorage, localStorage: Storage, sessionStorage: Storage, webkitStorageInfo: DeprecatedStorageInfo…}

严格模式
'use strict';
function test() {
 console.log(this);
};
test();
// undefined

var obj = {
 name: 'segmentFault',
 foo: function() {
  console.log(this.name);
 }
}
obj.foo();
// 'segmentFault'

function test() {
 console.log(this.name);
}
var obj = {
 name: 'qiutc',
 foo: test
}
obj.foo();
// 'qiutc'

 function a(a,b,c) {
    console.log(this.name);
    console.log(a,b,c)
  }
  const b = {
    name: "segmentFault"
  }
  a.call(b,1,2,3)    
  //输出 segmentFault和 1,2,3
  function a(a,b,c) {
    console.log(this.name);
    console.log(a,b,c)
  }
  a.apply(b,[1,2,3])
  //输出segmentFault和1,2,3

  function a() {
    console.log(this.name);
  }
  const b = {
    name: "segmentFault"
  }
  a.bind(b, 1, 2, 3)

  function a() {
    console.log(this.name);
  }
  const b = {
    name: "segmentFault"
  }
  const c = a.bind(b, 1, 2, 3)
  c()
  //此时输出segmentFault

 Function.prototype.myCall = function (context, ...arg) {
    const fn = Symbol('临时属性')
    context[fn] = this
    context[fn](...arg)
    delete context[fn]
  }

//实现自己的myApply
  Function.prototype.myApply = function (context, arg) {
    const fn = Symbol('临时属性')
    context[fn] = this
    context[fn](...arg)
    delete context[fn]
  }
  const obj2 = {
    a: 1
  }
  test.myApply(obj2, [2, 3, 4])

 //实现自己的myBind
  Function.prototype.myBind = function (context, ...firstarg) {
    const that = this
    const bindFn = function (...secoundarg) {
      return that.myCall(context, ...firstarg, ...secoundarg)
    }
    bindFn.prototype = Object.create(that.prototype)
    return bindFn
  }

  var fnbind = test.myBind(obj, 2)
  fnbind(3)

Function.prototype.myBind = function (objThis, ...params) {
  const thisFn = this; // 存储源函数以及上方的params(函数参数)
  // 对返回的函数 secondParams 二次传参
  let fToBind = function (...secondParams) {
    console.log('secondParams',secondParams,...secondParams)
    const isNew = this instanceof fToBind // this是否是fToBind的实例 也就是返回的fToBind是否通过new调用
    const context = isNew ? this : Object(objThis) // new调用就绑定到this上,否则就绑定到传入的objThis上
    return thisFn.call(context, ...params, ...secondParams); // 用call调用源函数绑定this的指向并传递参数,返回执行结果
  };
  fToBind.prototype = Object.create(thisFn.prototype); // 复制源函数的prototype给fToBind
  return fToBind; // 返回拷贝的函数
};