March 2020

JavaScript ES6: The forEach() Helper

forEach() is an ES6 helper that is used to call a function once on each item in an array. It’s iteration over an array or list.

In ES5, if we wanted to iterate over an array, we would make use of a for loop.

var colors = [ 'red', 'blue', 'green' ];

for( var i = 0; i < colors.length; i++) {

The ES5 for loop works fine. It will go through each item in an array and console log it but if an error occurs it can be challenging to see what’s going wrong, especially if there is lots of logic to follow. 

ES6 introduces the forEach() helper which can replace the for loop. But why bother doing it a different way? Well, I find the for loop has some disadvantages:

  • Lots of different elements of code.
  • Prone to typos.
  • Semicolons are between each element which is uncommon in JavaScript syntax.
  • The more logic in a single line of code the more difficult it is for future developers to understand what’s going on.

Now let’s see how the ES6 forEach() helper improves on the for loop.

var colors = [ 'red', 'blue', 'green' ];

colors.forEach(function(color) {

Ah, much cleaner! The forEach() helper improves on the for loop in a few ways:

  • Uses less code.
  • Less logic to get wrong.
  • Easier to read.
  • Removes the need of an iterator variable.

How forEach() Works

forEach() is an array helper method. When we call it we pass in an anonymous function which is the internal argument to the forEach() call. 

The function gets called one time for each item in the array and whatever is in the function, happens.

// 1. Create an array of numbers.
var numbers = [1, 2, 3, 4, 5];

// 2. Create a variable to hold the sum.
var sum = 0;

// 3. Loop over the array, incrementing the sum variable.
numbers.forEach(function(number) {
  sum += number;

// 4. print the sum variable.

Common convention is that in your array, you call it as a plural. So if we have an array containing numbers, we call the array “numbers”. 

In your iterator function, when we receive an individual element in that array then we’ll use the singular. In our “numbers” array we’ll use “number” in the iterator function.

The function in the forEach helper doesn’t have to be anonymous. We can declare it separately and then pass it into forEach. 

// 1. Create an array of numbers.
var numbers = [1, 2, 3, 4, 5];

// 2. Create a variable to hold the sum.
var sum = 0;

// 3. Create our adder function
function adder(number) {
  sum += number;

// 4. Loop over the array, incrementing the sum variable except this time a function gets referenced in the forEach

// 5. print the sum variable.

NOTE: When adding a function into the iterator we don’t use parentheses.


The ES6 forEach() is arguably the most useful ES6 helper. A lot of the other ES6 helpers could be reimplemented using forEach().

Whenever you want to call a function multiple times passing in a different argument each time, for each item in an array or list, we use the forEach() helper.

Continue Reading

  • March 2020

    Creating Interactive Accordions using jQuery

    Accordions are useful interface elements that, when clicked, will expand or condense the information on a web page. In this article, I will provide examples on how to create accordions and nested accordions using jQuery, and explain when you might want to use accordions.

  • March 2020

    5 Tips for Staying Productive While Working from Home

    For many of us, myself included, this will be your first experience working away from the office. To help you cope with the change, I've prepared 5 tips for staying productive while working from home.

  • Wheelchair users parking area

    September 2020

    Web Accessibility & Why its Crucial in 2021

    Web accessibility is all about inclusivity. It’s the idea that everyone, regardless of limitations, should have the same opportunity to view content on the web like everyone else. These limitations include visual, auditory or physical disabilities. Making your website accessible will become ever more crucial in 2021.

  • April 2020

    CodePen Challenge: Image Hovers

    This week's challenge prompt was to design a hover effect for an image. I created a simple effect that will jiggle the jelly when it is moused over!

Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now