How to Generate Unique ID in JavaScript

December 22, 2019

There are several ways to generate unique identifier in JavaScript. This could very useful in many cases, such as rendering list efficiently, or storing documents or records in database.

Using UUID

UUID is the abbreviation of univerally unique identifier, which is an identification number to uniquely identify something. The main idea of this thing is everytime we generate this numbers, it will be universally unique, which means no one could generate the exact same id as yours.

I personally prefer this approach in any case. In JavaScript, we can use a library called uuid to generate UUID.

$ npm install uuid
const uuidv4 = require("uuid/v4")


UUID has several versions, but the version that appropriate for generating unique id is version 4. And, that code will generate something like this.


Using Math.random

Math.random is a JavaScript built-in function which allows us to generate a random number. Which means that everytime we run it, it will return a unique combination of numbers.

Math.floor(Math.random() * 100)

Math.random always returns a decimal number, so we need to rounding off that number first. By multiply it with 100, it will return any number between 0 to 99. You can increase the number if you want to get better result.



Using is another JavaScript built-in function which allows us to get the number of miliseconds elapsed since January 1, 1970.



Express & Mongoose Course

By the way, I have a FREE video course for you on how to build a REST API using Express & Mongoose. Check it out and subscribe to my channel for more programming tutorials!


How to Upload Files with Multer

Uploading files is an essential feature for web applications these days. This tutorial will cover how to upload files into a server from the…


Full-Text Searching with Lunr.js

Lunr.js is a full-text search library for JavaScript. It allows us to perform a complex search to a collection of data. Its small, powerful…


How to Search an Array in JavaScript

In the previous tutorial, we learn about how we can do CRUD operations to an array in JavaScript. In this tutorial, we are going to learn…