A JavaScript insight.

What is Map() in JavaScript..? How to use it correctly.?

Looping using map() in JavaScript.

What is map() in JavaScript..?

map() is a looping construct used in JavaScript to loop through an array of elements.

How is a map() function used in JavaScript..?(Syntax)

Map() is invoked on an array and a callback function is passed in it, map() returns a new array.

The new array is a collection of element, where each element of it is nothing but the result of the element from initial array(numbers) after the function invocation.

Fig 1.1 An example for map function usage

fig 1.2: Output for above script

Why is map () used or Where can map() be used in JavaScript ..?

map() function is used to created a new array from the existing array, where the length of new array will be same as the existing array and all the elements of new array will not be same as existing array but related to it.

This relation is defined in a function, that is passed within the map().

The function within map() takes one element at a time from old array as argument and returns one element of new array. This performed for all the elements of old array.

Fig 2.1: Script for map

Fig 2.2: Flow Diagram of how control flows when map() is invoked on an array

map() can also be used for nested looping in case of array of array.