scope-call-bind-apply

// Use .bind() when you want that function to later be called
// with a certain context, useful in events.
// Use .call() or .apply() when you want to invoke the
// function immediately, with modification of the context.

// implement Function.prototype.bind()

/*
  const foo = function() {
    console.log(this.bar);

    let baz = foo.bind({bar: 'hello})

    baz(); // Hello
  }
*/

function bindWithCall(fn, context) {
  return function() {
    fn.call(context, arg1, arg2);
  };
}

function bindWithApply(fn, context) {
  return function() {
    fn.apply(context, [arg1, arg2]);
  };
}

// Bind returns a Bound Function Object that, when called
// calls the wrapped function with bound context
var object = { x: 9 };

var module = {
  x: 18,
  getX: function() {
    return this.x;
  }
};

console.log(module.getX());

var retrieveX = module.getX;

console.log(retrieveX());