New Built-in Classes: Set, Map, WeakSet, and WeakMap
We often use collections of objects when programming. In other languages, you may have used arrays, lists, sets, associative maps, or dictionaries. Sadly, JavaScript offered only arrays in the past.
When programmers needed a set or a map, they resorted to workarounds. These workarounds made the code hard to maintain, and when the code resulted in unintended behavior, we had more errors to deal with.
JavaScript now offers built-in classes for sets and maps as first-class citizens in the language. We will take a look at sets first and then maps. We will wrap up by looking at some special variations of these two classes for better memory use.
Using Set
The Array class that has been available ...
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