JavaScript Array map() Method

map()The method creates a new array and calls the provided function for each element in the array.

map()The method executes the callback function once for each array index.

Note : The map() method does not change the original array.

Syntax :

array.map(callback, thisArg)

Example

var nums1　= [1　5　20,　14　55　16]
var nums2　= nums1.map(twice);
function twice(element) {
　　　return (element　*　2);
}

The numbers in the table specify the first browser version that fully supports the map() method:

Method
map()	Is	1.5	Is	Is	9

Parameter	Description
callback	A function that is run for each element in the array. Function Parameters: element(Required)-The current element being processed in the array index(Optional)-The index of the current element being processed in the array array(Optional)- Called on the arrayMapping
thisArg	(Optional) Executecallbackis used asThisObject

Return Value:	A new array where each element is the result of a callback function
JavaScript Version:	ECMAScript 5

This example uses a number array and creates a new array containing the square roots of the numbers in the array:

Example

var nums1　= [4　9　16　25]
var nums2　= nums1.map(Math.sqrt);