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Advanced UUID Usage in JavaScript Applications

Alright, folks! Let’s dive into the world of UUIDs in JavaScript. If you’ve been around the block a few times, you’ll know that UUIDs (Universally Unique Identifiers) are the go-to when you need to generate a unique ID. Whether it’s for a database record, a session token, or just to tag your DOM elements like a graffiti artist, UUIDs are as unique as snowflakes and just as cool.

What’s a UUID Anyway?

UUIDs are 128-bit values that can guarantee uniqueness across space and time. They follow a standardized format, typically something like 123e4567-e89b-12d3-a456-426614174000. There are different versions of UUIDs, but we’ll focus on Version 4, which is based on random numbers.

Rolling Your Own vs. Using a Library

Now, you might be tempted to roll your own UUID generator. I get it, we like to DIY. But reinventing the wheel can be a risky business when it comes to something that needs to be universally unique. So, my advice? Use a library. It’s like getting a tattoo; you want a professional, not a DIY job with a needle and some ink.

UUID Generation in Vanilla JavaScript

Before we jump into libraries, let’s look at how you might generate a UUID in vanilla JavaScript. This is more of an educational exercise than a production-ready solution, but it’s cool to see under the hood.

function generateUUID() {
  let d = new Date().getTime();
  if (typeof performance !== 'undefined' && typeof === 'function'){
    d +=; // use high-precision timer if available
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    const r = (d + Math.random() * 16) % 16 | 0;
    d = Math.floor(d / 16);
    return (c === 'x' ? r : (r & 0x3 | 0x8)).toString(16);


This snippet uses math magic and current time to simulate a UUID. But remember, this is for funsies and learning. For the real deal, libraries are your friend.

Using uuid Library in Node.js

Node.js developers, rejoice! Generating a UUID in Node.js is as easy as pie with the uuid library. Let’s get down to business.

First, you need to install the uuid library:

npm install uuid

Now, let’s whip up some code to generate a UUID:

const { v4: uuidv4 } = require('uuid');

console.log(uuidv4()); // Outputs a fresh UUID, like a boss

Simple, right? You require the library, call the v4 method, and bam! You’ve got yourself a UUID.

Generating UUIDs in the Browser

“But what about the browser?” I hear you ask. Fear not, the uuid library has got you covered there, too.

First, you’ll want to install the library:

npm install uuid

Then, you can use it directly in your browser scripts:

import { v4 as uuidv4 } from 'uuid';

console.log(uuidv4()); // Look ma, a UUID in the browser!

Make sure your bundler is set up to handle this, or use a module bundler like Webpack or Parcel to get the job done.

UUIDs with crypto API

Modern browsers have a built-in crypto API, and it can be used to generate UUIDs. Here’s how you can do it:

function cryptoUUID() {
  return ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c =>
    (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)

console.log(cryptoUUID()); // A UUID that's as secure as your browser's crypto

This function uses the browser’s crypto API to generate random values, ensuring a good level of randomness and uniqueness.

Conclusion of Part One

We’ve just scratched the surface of UUIDs in JavaScript, and there’s more to explore. We’ve looked at generating UUIDs in vanilla JavaScript, Node.js, the browser, and even using the crypto API. Remember, while it’s fun to play around with generating UUIDs on your own, when it comes to real-world applications, it’s best to stick with tried-and-tested libraries to ensure true uniqueness and avoid any collisions.

Stay tuned for the second half of the article, where we’ll dive into more advanced topics like integrating UUIDs with databases, handling UUIDs on the client-side, and performance considerations. Happy coding, and may your IDs always be unique!

Welcome back, code warriors! In the first half, we covered the basics of UUIDs in JavaScript and how to generate them using various methods. Now, let’s level up and explore how to integrate UUIDs into real-world applications, handle them on the client-side, and consider performance implications.

Integrating UUIDs with Databases

When you’re dealing with databases, UUIDs can be a lifesaver for ensuring unique identifiers across distributed systems. Here’s how you can integrate UUIDs with some popular databases:


MongoDB uses a special type of UUID, but it’s still straightforward to store standard UUIDs as strings.

const { v4: uuidv4 } = require('uuid');
const { MongoClient } = require('mongodb');

const client = new MongoClient('your-mongodb-connection-string');

async function insertDocument() {
  try {
    await client.connect();
    const database = client.db('your-db-name');
    const collection = database.collection('your-collection-name');

    const document = {
      _id: uuidv4(),
      name: 'New Document',
      // other fields...

    const result = await collection.insertOne(document);
    console.log(`Document inserted with _id: ${document._id}`);
  } finally {
    await client.close();


In this snippet, we’re using the uuid library to generate a UUID and then inserting a new document with that UUID into a MongoDB collection.

SQL Databases (PostgreSQL, MySQL, etc.)

SQL databases like PostgreSQL and MySQL also support UUIDs. Here’s an example with PostgreSQL:

-- PostgreSQL table creation with UUID
    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
    name TEXT NOT NULL,
    -- other fields...

You’ll need to enable the uuid-ossp extension in PostgreSQL to use the uuid_generate_v4() function.

const { Pool } = require('pg');
const { v4: uuidv4 } = require('uuid');

const pool = new Pool({
  // connection config

async function insertItem() {
  const client = await pool.connect();
  try {
    const id = uuidv4();
    const name = 'New Item';
    const res = await client.query('INSERT INTO items(id, name) VALUES($1, $2) RETURNING *', [id, name]);
  } finally {


In this example, we’re inserting a new item into a PostgreSQL table with a UUID generated in JavaScript.

Handling UUIDs on the Client-Side

When working with UUIDs on the client-side, you might want to generate IDs for elements or manage sessions. Here’s how you can do that:

Generating UUIDs for DOM Elements

import { v4 as uuidv4 } from 'uuid';

function createUniqueElement() {
  const uniqueId = uuidv4();
  const newElement = document.createElement('div'); = uniqueId;
  newElement.innerHTML = 'This is a unique element!';


This function creates a new DOM element with a unique UUID as its ID.

Managing Session IDs

import { v4 as uuidv4 } from 'uuid';

function createSession() {
  const sessionId = uuidv4();
  sessionStorage.setItem('session_id', sessionId);

function getSession() {
  return sessionStorage.getItem('session_id');

console.log(`Session ID: ${getSession()}`);

Here we’re using UUIDs to create a unique session ID and store it in the browser’s sessionStorage.

Performance Considerations

UUIDs are generally larger and more complex than simple integer IDs, which can lead to performance considerations:

  • Indexing: UUIDs can be slower to index than integers. If performance is critical, consider using a sequential UUID generator or another strategy to mitigate this.
  • Storage: UUIDs take up more space. This usually isn’t an issue, but for extremely large datasets, it’s something to keep in mind.

Despite these considerations, UUIDs offer a level of uniqueness and flexibility that often outweighs the potential downsides.

Wrapping Up

We’ve now covered the A to Z of UUIDs in JavaScript, from generation to real-world application. Whether you’re building a web app, working with databases, or just need to tag something with a unique identifier, UUIDs are your trusty sidekick.

Remember, the key takeaways are to use libraries for generating UUIDs to ensure uniqueness and to be mindful of performance and storage implications when integrating UUIDs into your systems.

Happy coding, and may your data always stay unique and collision-free!