SOURCE

Function.prototype.myCall = function(obj,...arg) {
  obj._fn_ = this;
  obj._fn_(...arg);
  delete obj._fn_;
}

let o  ={
  name : 'o',
  fn: function() {
    console.log(this.name,...arguments);
  }
}

let test = {
  name : 'test'
}

console.log(o.fn(1,2,3));
console.log(o.fn.call(test,1,2,3));
console.log(o.fn.myCall(test,[1,2,3]))