Module JWT

@byu-oit-sdk/jwt

Requirements:

Node.js 18+
npm v9+

Installing

In addition to installing this module, you can install either the Jwt plugin for Fastify or for Express depending on what you're using.

npm install @byu-oit-sdk/jwt

Introduction

Use this module for verification and decoding of JWTs. Can be used in conjunction with the express and fastify plugins.

The current implementation uses jose internally for JWT verification and JWK handling.

This package exports the following:

Jwk - A class for verifying Jwks.
RsaJwk - A class for verifying RSA JWKs. Extension of the Jwk class.
JwkSet - A class which handles construction, validation, and loading of Jwk Sets.
createJwt() - A function that returns a class with methods for verifying and decoding JWTs.

Options

The following options can be passed in to the CreateJwt() function.

Option	Type	Default	Description
Schema	Object	REQUIRED OPTION	The schema of the payload of the JWT that you are creating.
transformer	function	-	The function that you will use for manipulating the JWT you are authenticating.
additionalValidations	array of functions	-	An optional array of functions that will also be used to validate the JWT.
key	string	REQUIRED OPTION	This is required but can be an empty string.
discoveryEndpoint	string	-	The redirection endpoint that the authorization server should redirect to after authenticating the resource owner.
issuer	string	-	Used to configure where the user will be sent to sign in.

Usage

TypeScript Coding Example

import { createJwt, Jwt, type JwtData } from '../src/Jwt.js'
import { type Static, Type } from '@sinclair/typebox'

const sampleJwtData = {
  header: {
    alg: 'HS256',
    typ: 'JWT'
  },
  payload: {
    id: 'some id',
    name: 'some Name'
  },
  signature: 'some signature'
}

const UserSchema = Type.Object({
  id: Type.String(),
  name: Type.String()
})

const TransformedJwtPayload = Type.Object({
  userId: Type.String(),
  userName: Type.String()
})

const jwtData: JwtData<Static<typeof UserSchema>> = {
  header: { alg: 'HS256', typ: 'JWT', kid: 'testKid' },
  payload: { id: '1', name: 'Alice' },
  signature: 'sample_signature'
}

const payloadTransformer = (payload: typeof UserSchema): Static<typeof TransformedJwtPayload> => {
  const userId = payload.id
  const userName = payload.name
  return {
    userId,
    userName
  }
}

const instance = new Jwt(jwtData, { transformer: payloadTransformer })

const CustomJwt = createJwt({
  schema: UserSchema,
  key: ''
})