JavaScript Algorithms Techniques: Frequency Map

What is a Frequency Map?

A frequency Map is a technique to calculate the frequency of an element in a Map for faster lookup.

Take the example below Array

Code

Building it using a plain Object

this is a good enough solution and widely accepted!

However, we do have a much more specific data structure in JavaScript now, which is much suited for this kind of problem.

and that would be…surprise…a Map

Let's modify the above solution with a Map

Building it using an ES6+ Map

Now, let's use in some problems

Examples:

JavaScript Interview Questions: Top K Frequent Elements