Javascript - Array forEach() Method

The forEach() method calls a provided function once for each element in an array.

Description

The forEach() method calls a provided function once for each element in an array.

forEach() does not run the function for array elements without values.

Syntax

array.forEach(function(currentValue, index, arr), thisValue)

Parameter Values

ParameterRequire Description
function(currentValue, index, arr) Required. A function to be run for each element in the array.
thisValue Optional. A value to be passed to the function to be used as its "this" value.If this parameter is empty, the value "undefined" will be passed as its "this" value

For function(currentValue, index, arr)

Argument Require Description
currentValue Required. The value of the current element
index Optional. The array index of the current element
arr Optional. The array object the current element belongs to

Example

List each item in the array:

Demo

var numbers = [4, 9, 16, 25];

function myFunction(item, index) {
    console.log( "index[" + index + "]: " + item + "\n");
}
numbers.forEach(myFunction);/*from  w  ww.  j a va  2 s  . co m*/

//Get the sum of all the values in the array:

var sum = 0;
var numbers = [6, 4, 2, 3];

function myFunction1(item) {
    sum += item;
    console.log( sum );
}
numbers.forEach(myFunction1);

//Multiply all the values in array with a specific number:

var numbers = [6, 4, 2, 3];

function myFunction2(item,index,arr) {
    arr[index] = item * 10;
    console.log(numbers);
}
numbers.forEach(myFunction2);

Result