JavaScript Index inside map() Function

Last Updated : 12 Jul, 2025

In JavaScript, the map() function’s callback provides an optional second parameter, the index, representing the current element's position in the array. This index starts at 0 and increments for each element, allowing access to each item’s position during iteration.

Syntax:

array.map(function(currentelement, index, arrayobj) {

 // Returns the new value instead of the item

});

Parameters: The Index inside function accepts three parameters as mentioned above and described below:

currentelement: The currentelement is a required argument in the map() which is the value of the current element.
index: The index is an optional argument map() which is an array index of provided current element.
arrayobj: The arrayobj is an optional argument in the map() which is the array object where the current element belongs.

Example 1: In this example we use map() to iterate over the student array. It alerts each student's name and their position in the top 5 ranks, incrementing the index by 1 for display.

Output:

Example: In this example we use map() to iterate over the webname array, displaying each element with a line break on the webpage and logging each element with its index to the console.

Output: