What are the data structures map and set used for?

map — is a collection of key-value pairs, where each value is associated with a unique key. It is used for quick search, addition, and removal of elements by key.

set — is a collection of unique values. It is used to store a set of non-repeating elements, check for the presence of an element, and perform set operations (union, intersection, difference).

Comparison:

	map	set
Stores	"key-value" pairs	Unique values
Access	By key	By value (presence check)
Keys/Values	Keys are unique	Values are unique
Usage	Dictionaries, caches, indices	Unique sets, filtering

Example of using map:

// Storing user data
const userInfo = new Map();
userInfo.set('name', 'Ivan');
userInfo.set('age', 30);
console.log(userInfo.get('name')); // Ivan

Example of using set:

// Getting unique elements of an array
const numbers = [1, 2, 2, 3, 4, 4, 5];
const uniqueNumbers = new Set(numbers);
console.log(uniqueNumbers); // Set(5) { 1, 2, 3, 4, 5 }
console.log(uniqueNumbers.has(3)); // true