How to use the map method to loop through an array in JavaScript
Overview
The map() method returns the new array after processing each element for the given array.
It accepts a callback function, which has currentItem as a mandatory parameter. We can hold this currentItem and process it as we like.
Syntax
const newArrayName = oldArray.map(callbackFun(currentItem, currentIndex, array))
Parameters
The map() method takes callbackFun as a parameter, and this callback function takes currentItem, currentIndex, and an array as parameters.
Return value
The map() method returns a new array with each element resulting from the callback function.
Example
Let's look at an example of using the map to loop through an array. In the following example, we'll get the square of each number present inside the array.
Code
Let's look at the code below:
const nums = [1, 2, 3, 4];// pass a callback function to mapconst squares = nums.map(x => x ** 2);console.log(squares);
Explanation
In the above code snippet:
- Line 1: We declare and initialize an array
nums. - Line 4: We loop through the array
numsusing themap()method and calculate the square of each element in the arraynums. We then store the returned new array in the variablesquares. - Line 6: We print the new array
squaresto the console.
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