What is JavaScript Array forEach() Method?

In this article, we will learn JavaScript Array forEach() Method,This free Javascript tutorial for complete beginners will help you learn Javascript from scratch.

JavaScript Array forEach() Method

JavaScript Array flatMap() Method

JavaScript Array includes() Method

The forEach() method calls a function for each element in an array. It does not return a new array and does not modify the original array. It’s commonly used for iteration and performing actions on each array element.

Syntax:

array.forEach(callback(element, index, arr), thisValue);

Parameters:

This method accepts five parameters as mentioned above and described below:

Parameter	Description
callback	This parameter holds the function to be called for each element of the array.
element	The parameter holds the value of the elements being processed currently.
index	This parameter is optional, it holds the index of the current value element in the array starting from 0.
array	This parameter is optional, it holds the complete array on which `forEach` is called.
thisArg	This parameter is optional, it holds the context to be passed as `this` to be used while executing the callback function. If the context is passed, it will be used as `this` for each invocation of the callback function, otherwise `undefined` is used as default.

Return value:

The return value of this method is always undefined. This method may or may not change the original array provided as it depends upon the functionality of the argument function.

Example 1: In this example, the Array.forEach() method is used to copy every element from one array to another.

JavaScript

// JavaScript to illustrate forEach() method
function func() {

    // Original array
    const items = [12, 24, 36];
    const copy = [];
    items.forEach(function (item) {
        copy.push(item + item + 2);
    });
    console.log(copy);
}
func();

Output

[ 26, 50, 74 ]

Example 2: In this example, the method forEach() calculates the square of every element of the array.

JavaScript

// JavaScript to illustrate forEach() method
function func() {

    // Original array
    const items = [1, 29, 47];
    const copy = [];
    items.forEach(function (item) {
        copy.push(item * item);
    });
    console.log(copy);
}
func();