A complete reference to Set in Javascript

Set

A Set is a special type of object in JavaScript that allows you to store unique values of any type, whether primitive values or object references. The duplicate values will be removed automatically that you attempt to add.

For example, if you have an array with duplicate values, you can easily convert it into a Set to filter out the duplicates.

const numbers = [1, 2, 3, 4, 4, 5, 5, 6];
const uniqueNumbers = new Set(numbers);
console.log(uniqueNumbers); // Output: Set(6) { 1, 2, 3, 4, 5, 6 }

We can also create a Set using the Set constructor.

var setObj = new Set(); // creates a empty set 

setObj.add(1);
setObj.add(2);
console.log(setObj); // Set(2) {1, 2}

setObj.add(1); // duplicate value will not be added.
console.log(setObj); // Set(2) {1, 2}

When Should You Use the Set Data Structure? 🤔

The Set data structure is ideal for scenarios where you need to store a collection of unique items. Common use cases include:

• Removing duplicates from arrays: Convert an array to a Set and back to remove any duplicate values.
• Efficient lookups: Checking if a value exists in a Set is generally faster than in an array, especially for large datasets.