Applications of Set in JavaScript

A Set is a collection of items that are unique i.e. no element can be repeated. Set in ES6 are ordered: elements of the set can be iterated in the insertion order. The set can store any type of value whether primitive or objects.

Application of Set in JavaScript:

• Deleting duplicates element from an array
• Creating a unique array from the unique values of two arrays
• Union of two sets
• Interaction of two sets

Approach 1: Deleting duplicates element from an array

In this approach, we are given a set with multiple duplicate values and we will remove the duplicates from the set.

Example:

Javascript

// Create an array containing duplicate items
const duplcateArray = [
    2, 3, 4, 8, 8, 9, 9, 4, 2,
    3, 3, 4, 6, 7, 5, 32, 3, 4, 5
];

// Use Set and Spread Operator to remove
// duplicate items from an array
console.log([...new Set(duplcateArray)]);

Output:

[ 2, 3, 4,  8, 9, 6, 7, 5, 32 ]

Approach 2: Creating a unique array from the unique values of two arrays

In this approach, we will create a unique array from the unique value of two arrays.

Example:

Javascript

// Declare first array
const arr1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

// Declare second array
const arr2 = [7, 8, 9, 10, 6, 11, 12, 13];

// Function to get the unique values array
// from two arrays
function uniqueArray(arr1, arr2) {
    const set = new Set(arr1.concat(arr2));
    return Array.from(set);
}

// Display the array containing
// unique values
console.log(uniqueArray(arr1, arr2));

Output

[
   1, 2, 3,  4,  5,  6,
   7, 8, 9, 10, 11, 12,
  13
]

Approach 3: Union of two sets

In this approach, we will join the values of two sets

Example:

Javascript

// Create first set
let a = new Set([1, 2, 3]);

// Create second set
let b = new Set([4, 3, 2]);

// Use spread Operation to Merge both
// set and then use Set() constructor
// to get union of both set
let union = new Set([...a, ...b]);

// Display the result
console.log(union)

Output:

{ 1, 2, 3, 4 }

Approach 4: Interaction of two sets

In this approach, we will get the intersection of two sets.

Example:

Javascript

// Create first set
let a = new Set([1, 2, 3]);

// Create second set
let b = new Set([4, 3, 2]);

// Get the instersection of both set
let intersection = new Set(
    [...a].filter(x => b.has(x)));

// Display the result
console.log(intersection)

Output

Set(2) { 2, 3 }