When to use the bind function?

bind-function-in-JavaScript.js

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

console.log(fullName()); // Output: Hello, this is undefined undefined

// create a person object and pass its values to the fullName function
var person = {first: "Foo", last: "Bar"};

// pass a person object to the fullName function using bind
// bind object to function -> fullName.bind(person)
// self call a function -> fullName.bind(person)()
console.log(fullName.bind(person)()); // Output: Hello, this is Foo Bar