Implement apply call bind

apply

use ES6

Function.prototype.myCall = function(obj, ...args) {
  if (obj === null || obj === undefined) {
    obj = window;
  } else {
    obj = Object(obj);
  }
  obj._fn = this;
  obj._fn(...args);
  delete obj._fn;
}

var test = {
  name: 'test'
}

var obj = {
  name: 'obj',
  fun: function() {
    console.log(this.name, ...arguments);
  }
}

obj.fun(1,2,3);                     // obj 1 2 3
obj.fun.myCall(test, 1,2,3)         // test 1 2 3

use eval

Function.prototype.myCall = function(obj) {
  if (obj === null || obj === undefined) {
    obj = window;
  } else {
    obj = Object(obj);
  }
  let arg = [];
  for(let i=1; i < arguments.length; i++) {
    arg.push('arguments[' + i + ']');
  }
  obj._fn = this;
  eval('obj._fn(' + arg + ')');
  delete obj._fn;
}
var test = {
  name: 'test'
}

var obj = {
  name: 'obj',
  fun: function() {
    console.log(this.name, ...arguments);
  }
}
obj.fun(1,2,3);                     // obj 1 2 3
obj.fun.myCall(test, 1,2,3)         // test 1 2 3

call

use ES6

Function.prototype.myApply = function(obj, arr) {
  if (obj === null || obj === undefined) {
    obj = window;
  } else {
    obj = Object(obj);
  }
  obj._fn = this;
  obj._fn(...arr);
  delete obj._fn;
}
var test = {
  name: 'test'
}

var obj = {
  name: 'obj',
  fun: function() {
    console.log(this.name, ...arguments);
  }
}
obj.fun([1,2,3]);                     // obj 1 2 3
obj.fun.myApply(test, [1,2,3])         // test 1 2 3

use eval

Function.prototype.myApply = function(obj, arr) {
  if (obj === null || obj === undefined) {
    obj = window;
  } else {
    obj = Object(obj);
  }
  let args = [];
  let val ;
  for(let i = 0 ; i < arr.length ; i++){
      args.push( 'arr[' + i + ']' ) ;
  }
  obj._fn_ = this;
  val = eval( 'obj._fn_(' + args + ')' );
  delete obj._fn_;
  return val
}
var test = {
  name: 'test'
}

var obj = {
  name: 'obj',
  fun: function() {
    console.log(this.name, ...arguments);
  }
}
obj.fun(1,2,3);                     // obj 1 2 3
obj.fun.myCall(test, 1,2,3)         // test 1 2 3

bind

Function.prototype.myBind = function(obj, ...arg1) {
  return (...arg2) => {
    let args = arg1.concat(arg2);
    obj._fn = this;
    obj._fn(args);
    delete obj._fn;
  }
}

Update at 2020-04-02

call

Function.prototype.myOwnCall = function(someOtherThis) {
    someOtherThis = someOtherThis || global;
    var uniqueID = "00" + Math.random();
    while(someOtherThis.hasOwnProperty(uniqueID)) {
        uniqueID = "00" + Math.random();
    }
    someOtherThis[uniqueID] = this;
    const args = [];
    for(let i = 1, len = arguments.length; i < len; i++) {
        args.push("arguments[" + i + "]");
    }
    var result = eval("someOtherThis[uniqueID](" + args + ")");
    delete someOtherThis[uniqueID];
    return result;
}

apply

Function.prototype.myApply = function(someOtherThis, arr) {
    someOtherThis = someOtherThis || global;
    var uniqueID = "00" + Math.random();
    while(someOtherThis.hasOwnProperty(uniqueID)) {
        uniqueID = "00" + Math.random();
    }
    someOtherThis[uniqueID] = this;
    var result = null;
    var args = []
    if(!arr) {
        result = someOtherThis[uniqueID]();
    } else {
        for(let i = 0, len = arr.length; i < len; i++) {
            args.push("arr[" + i + "]")
        }
        result = eval("someOtherThis[uniqueID](" + args + ")");
    }
    delete someOtherThis[uniqueID];
    return result;
}

function showProfileMessage(message) {
    console.log(message, this.name);
   }
   const obj = {
    name: "Ankur Anand"
   };
showProfileMessage.myApply(obj, ["welcome "]);  // welcome  Ankur Anand

bind

if(!Function.prototype.bind) {
    Function.prototype.bind = function(obj) {
        if (typeof this !== "function") {
            throw new Error(this + "cannot be bound as it's not callable");
        }
        var args = Array.prototype.slice.call(arguments, 1),
            bindThis = this,
            fNOP = function() {},
            fBound = function() {
                return bindThis.apply(
                    this instanceof fNOP ? this : obj,
                    args.concat(Array.prototype.slice.call(arguments))
                )
            };
        if(this.prototype) {
            fNOP.prototype = this.prototype;
        }
        fBound.prototype = new fNOP();
        return fBound;
    }
}

var person = {
    lastName: "Anand"
  };
  
  function fullName(salutaion, firstName) {
    console.log(salutaion, firstName, this.lastName);
  }
  
  var bindFullName = fullName.bind(person, "Mr");
  
  bindFullName("Ankur");        // Mr Ankur Anand