Maps and Sets
Maps and Sets are very underrated types in JavaScript, but they can be very powerful in some applications. Maps work just like a basic hashmap in JavaScript, and are useful when you need to keep track of a list of key-value pairs. Sets are used when you need to keep a list of unique values. Most developers often use objects for everything while forgetting that, in some cases, using Maps and Sets is way more efficient. In the following section, we will go over Maps and Sets and how to use them.
There are many cases where we must keep track of a list of unique key-value pairs in our application. When programming with other languages, we often need to implement a class called Hashmap. In JavaScript, there are two types that can accomplish this: one is Map and the other is Object. Because they seem to do the same thing, many JavaScript developers tend to use Object for everything while ignoring that using Map is sometimes way more effective for their use case.