Skip to content

call() and apply() in JavaScript



Find out how to use call() and apply() and their difference in JavaScript

call() and apply() are two functions that JavaScript offers to perform a very specific task: call a function and set its this value.

Check out my β€œthis” guide to know all the details about this particular variable

A function can use the this value for many different use cases. The problem is that it’s given by the environment and cannot be changed from the outside, except when using call() or apply().

When using those methods, you can pass in an additional object that will be used as this in the function invoked.

Those functions perform the same thing, but have a difference. In call() you can pass the function parameters as a comma separated list of parameters, taking as many parameters as you need, while in apply() you pass a single array that contains the parameters:

const car = {
  brand: 'Ford',
  model: 'Fiesta'

const drive = function(from, to, kms) {
  console.log(`Driving for ${kms} kilometers from ${from} to ${to} with my car, a ${this.brand} ${this.model}`)
}, 'Milan', 'Rome', 568)
drive.apply(car, ['Milan', 'Rome', 568])

Note that when using arrow functions this is not bound, so this method only works with regular functions.

  • Learn modern web development in my BOOTCAMP (SIGNUP END TOMORROW FEB 20, 2024)
  • THE VALLEY OF CODE (+ PRO), your web development manual
  • I wrote 15+ coding BOOKS, all available in THE VALLEY OF CODE PRO
  • Indie solopreneur internet business masterclass SOLO LAB (summer 2024)