Apply vs. Call vs. Bind javascript example

Apply vs Call vs Bind Examples

Call

var person1 = {firstName: 'pranay', lastName: 'soni'};

var person2 = {firstName: 'test_f', lastName: 'test_l'};

function say(greeting) {

console.log(greeting + ' ' + this.firstName + ' ' + this.lastName);

}

say.call(person1, 'Hello'); // Hello pranay soni

say.call(person2, 'Hello'); // Hello test_f test_l

Apply

var person1 = {firstName: 'pranay', lastName: 'soni'};

var person2 = {firstName: 'test_f', lastName: 'test_l'};

function say(greeting) {

console.log(greeting + ' ' + this.firstName + ' ' + this.lastName);

}

say.apply(person1, ['Hello']); // Hello pranay soni

say.apply(person2, ['Hello']); // Hello test_f test_l

Bind

var person1 = {firstName: 'pranay', lastName: 'soni'};

var person2 = {firstName: 'test_f', lastName: 'test_l'};

function say() {

console.log('Hello ' + this.firstName + ' ' + this.lastName);

}

var sayHelloPranay = say.bind(person1);

var sayHelloTest = say.bind(person2);

sayHelloPranay(); // Hello pranay soni

sayHelloTest(); // Hello test_f test_l

When To Use Each

Call and apply are pretty interchangeable.

Just decide whether it’s easier to send in an array or a

comma separated list of arguments.

I always remember which one is which by remembering that Call is for

comma (separated list) and Apply is for Array.

Bind is a bit different. It returns a new function.

Call and Apply execute the current function immediately.