While working on a real life project we often have front end separated from backend by API, which is a standard modern method as of today. But the data given by backend API is not always favorable for the frontend. And such scenario in real life is imminent and it is not always possible to write a new API for every desirable data in frontend which can be manipulated. But this scenario is not necessarily only useful on frontend, but also could prove very significant on backend too. map creates a new array by transforming every element in an array, individually. filter creates a new array by removing elements that don't belong. reduce , on the other hand, takes all of the elements in an array, and reduces them into a single value. map → Executes a function on each element of an array filter → Remove items which don’t satisfy a condition Reduce → Creates a single value from elements of Array Array.prototype.map() The map() method ...
Bunch of tutorials on how and why things are done