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 : 1697  
 
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

Difference between arrow and normal functions in JavaScript

In this tutorial we are going to see how arrow functions differ from normal JavaScript functions. We will also see when you should use one and when you should use…

JavaScript Arrow functions: What they are and how to use them

In this article we are going to see what they are and how to use JavaScript Arrow Functions, a new feature introduced with the ES6 standard (ECMAScript 6). What are Arrow…

How to insert an element into an array with JavaScript

In this brief tutorial you will learn how to insert one or more elements into an array with JavaScript. For this we will use the splice function. The splice function will not…

What is the difference between primitives types and objects in JavaScript?

In this short tutorial we are going to look at the differences between primitive types and objects in JavaScript. To start with, we're going to look at what primitive types…

How to get DOM elements with JavaScript

When you access any element of the DOM, it is usual to save it in a variable. This is something that at first might seem very simple, but if you…

How to reverse an array in JavaScript

In this tutorial we are going to see how you can change the order of the elements of an array so that they are inverted. You could use a loop…

How synchronize the scroll of two divs with JavaScript

In case you have two divs of different sizes you may sometimes want to scroll both at the same time but at different speeds depending on their size. For example,…

How to use the codePointAt method in JavaScript

The JavaScript codePointAt method has more or less the same function as the charCodeAt method, used to get the 16-bit Unicode representation of the character at a certain position in…

How to check if a value is a number in JavaScript

In this short tutorial we are going to look at the various methods that exist to find out if a value is a number in JavaScript.   1. Using the isNaN() function   One…

How to use the charCodeAt method in JavaScript

The charCodeAt method is accepted by strings in JavaScript, returning the 16-bit Unicode code of the character at the position we pass as a parameter to the method. The charCodeAt method…

How to use the charAt method in JavaScript

The charAt method is accepted by strings in JavaScript, returning the position of the character passed as a parameter within the string. If the string contains multiple occurrences of the character…

Strings in JavaScript: What they are and how to use them

In this tutorial we are going to explain what strings are and how they are used in JavaScript. The tutorial is intended for people who are learning to program in…

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