Generate a UUID in JavaScript

How to Generate a UUID in JavaScript

Although the JavaScript language itself does not have built-in support for generating a UUID or GUID, there are plenty of quality 3rd party, open-source libraries that you can use.

The JavaScript library we recommend for generating UUIDs is called (unsurprisingly), uuid. It can generate version 1, 3, 4 and 5 UUIDs.

Installing the uuid Package

To get started with the library, you'll need to install it. If you're working in a project with a package.json file, run this command to add it to the dependencies list:

% npm install uuid

Or if you want to install it globally on your computer, use this command:

% npm install -g uuid

Generating UUIDs

With the uuid library installed, you can now use it in your JavaScript code.

Here's how you can generate a version 4 UUID in JavaScript with the uuid library:

import {v4 as uuidv4} from 'uuid';

let myuuid = uuidv4();

console.log('Your UUID is: ' + myuuid);

Explanation

• Line #1 imports the version 4 UUID function. There are also functions available for generating version 1, 3 and 5 UUIDs. Note that this is the ES6 module import syntax.
• Line #3 generates the UUID and saves it in the variable, myuuid.
• The output from line #5 will be something like:

  Your UUID is: c32d8b45-92fe-44f6-8b61-42c2107dfe87
  

The uuid library has a number of other functions, such as for converting from a string representation of a UUID into a byte array and back. You can read more about the JavaScript uuid library on it's GitHub page.

How to Generate a UUID in a Browser

If your Javascript code will execute within a secure browser context, such as on a page served via HTTPS, you can also use the browser's global crypto property to generate a cryptographically secure, version 4 UUID.

The crypto object provides access to the Web Crypto API and has functions defined in the Crypto interface. For our discussion, we can use the global crypto object to generate version 4 UUIDs using the randomUUID() function:

let myuuid = crypto.randomUUID();

console.log('Your UUID is: ' + myuuid);

Explanation

• Line #1 generates the UUID and saves it in the variable, myuuid.
• The output from line #3 will be something like:

  Your UUID is: c32d8b45-92fe-44f6-8b61-42c2107dfe87
  

Although the crypto object is available in both secure and insecure contexts, it is not recommended for use in insecure contexts.

The crypto property be accessed globally in a browser context or web worker, e.g. crypto or window.crypto, or self.crypto depending on the context.

Other Options for Generating UUIDs in Javascript

To generate version 7 UUIDs, you can use the uuidv7 package.

// Install the uuidv7 package.
// npm install uuidv7

import { uuidv7 } from 'uuidv7';

let myuuid = uuidv7();

console.log('Your UUID is: ' + myuuid);

Explanation

• Line #2 shows the command needed to install the uuidv7 package: npm install uuid7
• Line #4 imports the version 7 UUID function. There are also functions available for generating version 4 UUIDs as well as functions for obtaining the raw bytes.
• Line #6 generates the version 7 UUID and saves it in the variable, myuuid.
• The output from line #8 will be something like:

  Your UUID is: 018b2f0a-45a7-778b-88b7-da6933b704a3
  

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