You probably know about Function.prototype.bind method in JavaScript. It returns a copy of the original function but this function will always be called in the specified context. The problem is that you can't rebind another context any more. var func = function () { return this.prop; }; var obj1 = {prop: 1}, obj2 = {prop: 2}; func = func.bind(obj1); func(); // Will produce 1 func = func.bind(obj2); func(); // Will also produce 1 :( Your task is override the native Function.prototype.bind method by a new one that will allow you to rebind context multiple times. In this kata you don't need to worry about currying, testing function will never get params. Node version 8

Function.prototype.bind = function (newThis) {
  const func = this;
  return function () {
    return func.apply(newThis, arguments);
  };
};