JavaScript Sets

Set is one of the new Data Structures that got added to JS with ES6.

• Sets are not ordered like array but iterable
• Sets can only have unique values even if we added duplicate values

//we can create sets like this
const mySet = new Set([1, 2, 2, 5, 5]);
const mySet2 = new Set(['pizza','pasta', 'fries','burger','pizza', 'cheese']);
const mySet3 = new Set('abdelrahman');
console.log(mySet,mySet2,mySet3);
//Set(3) {1, 2, 5}  //no duplicates
//Set(5) {'pizza', 'pasta', 'fries', 'burger', 'cheese'}
//Set(9) {'a', 'b', 'd', 'e', 'l', 'r','h','m','n'}

• We can get set size like that
• size of the unique values only

console.log(mySet.size); //3

• we can also check element is in the set or not

console.log(mySet.has(2));//true 
console.log(mySet2.has('milk'));//false 

• we can add and delete values from a Set

mySet.add(10);
mySet.delete(2);
console.log(mySet);//{1, 5, 10}

• there is no way of retrieving values from a set that’s because if all values are unique and if their does not matter there is no point of retrieving values out of a set and if your goal is to actually store values in order then the best use case is an Array

• we can iterate over a set cause they are iterable as we said before
  

for(const item of mySet) console.log(item);
// 1
// 5
// 10

• the main use cause of sets is actually to remove duplicate values from arrays

const arr = [10,10,20,20,30];
const uniqueArr = new Set(arr);
console.log(uniqueArr); //{10, 20, 30}

//if u want to save the unique values to an array again u can use the spread operator like that cause it work on all iterables
const uniqueArr = [...new Set(arr)];
console.log(uniqueArr); //[10, 20, 30]

• and finally u can delete all set element by using clear method

arr.clear();