What is the difference between call and apply?

Question

What is the difference between using call and apply to invoke a function?

var func = function() {
  alert(\'hello!\');
};
         


        

Answer 1

Call and apply both are used to force the this value when a function is executed. The only difference is that call takes n+1 arguments where 1 is this and 'n' arguments. apply takes only two arguments, one is this the other is argument array.

The advantage I see in apply over call is that we can easily delegate a function call to other function without much effort;

function sayHello() {
  console.log(this, arguments);
}

function hello() {
  sayHello.apply(this, arguments);
}

var obj = {name: 'my name'}
hello.call(obj, 'some', 'arguments');

Observe how easily we delegated hello to sayHello using apply, but with call this is very difficult to achieve.