What actually bind in Javascript

The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.

const module = {

  x: 42,

  getX: function() {

    return this.x;

  }

};

const unboundGetX = module.getX;

console.log(unboundGetX()); // The function gets invoked at the global scope

// Expected output: undefined

const boundGetX = unboundGetX.bind(module);

console.log(boundGetX());

// Expected output: 42

The output :

> undefined > 42

Source :  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind