Javascript - Array forEach() Method

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

Parameter	Require	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 w w . ja  v  a  2 s.  c o  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);