Merge Set Objects using JavaScript

The Set object allows you to store unique values ​​of any type, whether primitive values ​​or object references.

var merged = new Set([...set1, ...set2, ...set3])

How to merge Maps using JavaScript

A Map object stores key-value pairs and remembers the original order in which the keys were inserted. Any value (both objects and primitive values) can be used as a key or value.

var merged = new Map([...map1, ...map2, ...map3])