When would you use the bind function?

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.

A good use of the bind function is when you have a particular function that you want to call with a specific this value. You can then use bind to pass a specific object to a function that uses a this reference.

function fullName() {
  return "Hello, this is " + this.first + " " + this.last;
}

console.log(fullName()); // => Hello this is undefined undefined

// create a person object and pass its values to the fullName function
var person = {first: "Foo", last: "Bar"};
console.log(fullName.bind(person)()); // => Hello this is Foo Bar