The JavaScript forEach loop

by Janeth Kent Date: 20-05-2021 javascript

We have already talked about how to handle some of loops  types in Javascript including for, for-in and for-off loops. In the case of today we are going to see how we can make a foreach loop in Javascript.

A foreach loop helps us in a simple way to go through the elements of an array. So the first thing we'll do is create our list of elements. In this case we have created a list of countries as follows:

const countries=['Italy','Spain','France','Holand','Germany','England','Greece','Ireland'];

Before moving on to foreach loops, let's remember that for traversing lists of elements we have seen that for-loops have a format more or less similar to the following:

for (initial_value;control;increment) {    
// Rules 

However, we have to get this structure out of our minds. And is that in the case of the foreach loop in Javascript this is a method of the Array object, not a loop to the use, with the following structure:

countries.forEach(function(item,index) { });

As we can see the method receives a callback function with two elements, on the one hand the item that will be the element on which it will iterate and on the other hand the index that it occupies in the list. In this way the code that we have inside the function will be executed for each of the elements that we have inside the list.

The function can be an anonymous function within the .forEach() method or we can define it and assign it to the method.

In this way, we could display the array elements on the screen with the forEach() method in the following way:

countries.forEach(function(item,index) {      
     console.log("The country" + item + "position is:" + index);  

In this simple way we will have executed a foreach loop in Javascript.

by Janeth Kent Date: 20-05-2021 javascript hits : 1184  
Janeth Kent

Janeth Kent

Licenciada en Bellas Artes y programadora por pasión. Cuando tengo un rato retoco fotos, edito vídeos y diseño cosas. El resto del tiempo escribo en MA-NO WEB DESIGN END DEVELOPMENT.


Related Posts

Dates in local format with Javascript

In the articles we have about dates in JavaScript we were missing one about how to create dates in local format with JavaScript. That is to say, being able to…

Formatting hours in Javascript

Continuing with the set of articles that talk about internationalisation elements, like the previous one where we talked about relative dates in JavaScript, we will see in this one how…

Request data with prompt in JavaScript

After having published several articles about how to manipulate arrays and dates, today I will publish a post that some of you will find too basic and others will find…

Relative dates in JavaScript

One of the interesting things about the internationalisation library represented in the Int object is the handling of relative dates in Javascript. This handling allows us to represent a date…

How to access webcam and grab an image using HTML5 and Javascript

We often use webcams to broadcast video in real time via our computer. This broadcast can be viewed, saved and even shared via the Internet. As a rule, we need…

What are React Hooks and what problems they solve

Working with React, - and before the release of Hooks in version 16.8 -  there was always the possibility to create components in three different ways based on a number of…

Flattening arrays in JavaScript

When we are handling arrays that are arrays or have multiple dimensions it can be very useful to know how to flatten arrays in JavaScript. That is to say, to…

How to populate an array with random numbers in JavaScript

Some of you might think that what we explained in the article on how to populate an array with numbers, apart from the didactic part, would not have much applicability…

How to populate an array with numbers in JavaScript

Populate an array with numbers in JavaScript The first step is to initialise the array. So today we are going to see a simple way to do it and see how…

Top Javascript Libraries and Frameworks Part 2

What are JavaScript frameworks?   JavaScript frameworks are application frameworks that allow developers to manipulate code to meet their particular needs. Web application development is like building a house. You have the option…

How to Send Email from an HTML Contact Form

In today’s article we will write about how to make a working form that upon hitting that submit button will be functional and send the email (to you as a…

Top JavaScript libraries and frameworks part 1

JavaScript libraries and frameworks make it easy to develop websites and applications with a wide variety of features and functionality, all with dynamic, flexible and engaging features. According to a 2020…

We use our own and third-party cookies to improve our services, compile statistical information and analyze your browsing habits. This allows us to personalize the content we offer and to show you advertisements related to your preferences. By clicking "Accept all" you agree to the storage of cookies on your device to improve website navigation, analyse traffic and assist our marketing activities. You can also select "System Cookies Only" to accept only the cookies required for the website to function, or you can select the cookies you wish to activate by clicking on "settings".

Accept All Only sistem cookies Configuration