How to use Map, Reduce, and Filter in JavaScript?

Here’s how to use the core array methods used in Functional Programming.

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Developers and beginners still seem confused about these three array methods irrespective of the articles on Medium, freeCodeCamp, or any other platform.

I decided to explain these methods once again in simple and precise language. I’m contributing and adding to the other great articles on this topic.

Let’s start with the map()method.

Map

First, the Map object, a key-pair-based data structure, is not the map()method. Both of them solve different problems. They are not related or the same. We address the former as an Object and the latter as a method (function).

The map method allows you to run a callback function on each element of an array without modifying the original array. It creates a new duplicate array and scans through each element like a standard loop.

It has three arguments. The first one represents a variable that will hold the current element of the repetition. The second one stores the index of the current element in the loop from the array. The third…