FusionAuth OAuth2 Client

A TypeScript/JavaScript client for FusionAuth's OAuth2 Authorization Code Flow.

Features

• Start the OAuth2 Authorization Code Flow
• Exchange authorization code for access token
• Fetch user info
• Type-safe configuration and responses

Installation

npm install @properdo/fusionauth-oauth2-client

Usage

1. Import and configure the client

import { CodeFlow } from '@properdo/fusionauth-oauth2-client';

const client = new CodeFlow({
  clientId: 'YOUR_CLIENT_ID',
  clientSecret: 'YOUR_CLIENT_SECRET',
  redirectUri: 'http://localhost:5545/oauth2callback',
  oauth2Host: 'https://auth.example.com',
  scope: 0, // or use bitwise OR of AddressScope, EmailScope, etc.
});

Understand setting scope of OAuth2

Scopes can be set with bitwise OR, there are 4 scopes in total: AddressScope, EmailScope, ProfileScope, PhoneScope.

import { CodeFlow, AddressScope, EmailScope } from '@properdo/fusionauth-oauth2-client';

const client = new CodeFlow({
  ...
  // This will call OAuth2 code flow with scope AddressScope and EmailScope, resulting the profile getting also contains the address and email of the user
  scope: AddressScope | EmailScope
});

However, you can also not setting any scope at all by putting number 0:

const client = new CodeFlow({
  ...
  scope: 0,
});

This will call OAuth2 code flow with 0 scope. With this, you also get the access_token that verifies the user is indeed logged in on FusionAuth, but calling getUserInfo(access_token) will result error as we do not have the specified scope to get user information !!!

2. Get the authorization URL

const startUrl = client.start();
// Redirect the user to startUrl

3. Exchange code for access token

const code = 'CODE_FROM_QUERY_STRING';
const tokenResponse = await client.getAccessToken(code);

if ('access_token' in tokenResponse) {
  // Success
  console.log('Access Token:', tokenResponse.access_token);
} else {
  // Error
  console.error(tokenResponse.error_description);
}

4. Fetch user info

// The accessToken is taken from function `getAccessToken`;
// This will cost 1 additional request to the FusionAuth server
const accessToken = 'ACCESS_TOKEN';
const userInfo = await client.getUserInfo(accessToken);
console.log(userInfo);

License

MIT