How does newSet() work?

Question

JavaScript

I can't figure out how the new Set() method works. How does it create uniqueness? For example, I have an array let a = ['Q', 'W', 'E', 'W', 'R', 'R']how to remove duplicate letters using new Set(). To return ['Q', 'W', 'E', 'R']. With the help of filter () I can do it, but new Set () has not yet been parsed.

Answer 1

https://learn.javascript.ru/map-set#set
[...new Set(a)]