Pluggable facade for OAuth authentication in the browser

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OIT work towards a unified OAuth framework for our frontend libraries.
This library provides a facade around OAuth authentication on the frontend.
In and of itself, this library does not know how to perform authentication. It does, however, provide a pluggable, event-based system for sharing authentication information between an application and any shared API client libraries or Web Components which it uses.
Shared libraries and UI components that require OAuth bearer tokens to make API calls should depend on this library, and should bundle this library into their deployment artifacts.
Applications which use any such libraries or components must then use a compatible OAuth provider library:
  • https://github.com/byuweb/byu-browser-oauth-implicit
  • (others will be listed when they are created)

Applications may also wish to depend on this library directly.
Installing and using
At this time, this library is intended to be bundled into any libraries or applications that use it.
Installation is via NPM or Yarn:
npm install --save @byuweb/browser-oauth

yarn add @byuweb/browser-oauth
API Overview
The library is distributed as an ES Module.
import * as authn from './node_modules/@byuweb/browser-oauth/byu-browser-oauth.js';


For an Implicit Grant implementation of byu-browser-oauth go to https://github.com/byuweb/byu-browser-oauth-implicit and follow the instructions before proceeding.
Once you have completed the instructions in the implicit grant, you can add the observer to your project to get info about the user, token, and authentication state.
const observer = new authn.AuthenticationObserver(({state, token, user, error}) => {
    // React to change

Data Types

There are three main data types: User, Token, and AuthenticationError.


    personId: '',
    byuId: '',
    netId: '',
    name: {
        sortName: 'Student, Joseph Q',
        displayName: 'Joe Student', //constructed from givenName, familyName, and familyNamePosition
        givenName: 'Joe', //preferred first name
        familyName: 'Student',
        familyNamePosition: 'L', //or 'F', for 'Last' and 'First'
    rawUserInfo: {}, //provider-specific version of the user info object.


    bearer: '',
    authorizationHeader: '',
    expiresAt: new Date(),
    client: {
        id: '',
        byuId: '',
        appName: '',
    rawUserInfo: {}, //provider-specific version of the user info object.


AuthenticationObserver allows you to be notified when the authentication state changes.
const observer = new authn.AuthenticationObserver(({state, token, user, error}) => {
    // React to change

When an AuthenticationObserver is created, the authentication provider will be immediately queried for its current state, and will pass that state to the callback. If you wish to disable this immediate callback, set the notifyCurrent option to false:
const observer = new authn.AuthenticationObserver(({state, token, user, error}) => {
    // React to changes, but not the initial state
}, { notifyCurrent: false });

When you're done with the observer, like in the disconnectedCallback() method of a Web Component, call disconnect()
const observer = authn.onStateChange(({state, token, user, error}) => {
    // React to change

//in disconnectedCallback():

Authentication States

State Name | Meaning -----------|--------- authn.STATE_INDETERMINATE | Initial state. The authentication library is still initializing and retrieving state from the provider. authn.STATE_AUTHENTICATING | The user is not yet authenticated, but the provider is working on authenticating them. authn.STATE_AUTHENTICATED | The user is fully-authenticated. authn.STATE_UNAUTHENTICATED | There is no authenticated user. authn.STATE_ERROR | An authentication error ocurred. If this is the case, onStateChange will receive an 'error' parameter with details. authn.STATE_EXPIRED | The user's token has expired. It may still be valid for a short amount of time, but the application should take steps to refresh the token. authn.STATE_REFRESHING | The provider is in the process of refreshing an expired token.

Current Values

Helper function are provided to get the current authentication state. These functions all return a Promise with the requested value.


Get the current authentication state.


Resolves to true if there is a current, unexpired authentication token.


Gets the current authentication token object.


If we have a current token, get the computed Authorization header value.


Get the current user object

Request Actions

An application can request that the provider attempt to log in a user, log out a user, or refresh the user's session.
All of these functions return a promise that will resolve or reject when the requested action has been completed. However, most authentication providers will need to navigate the user to an OAuth authorization server, and in those cases, these promises will not resolve before the page is unloaded.
Shared libraries and UI components generally should not call these functions.


Causes the authentication provider to begin a login process.
    .then(({state, token, user, error}) => {
        // If we don't have to redirect the browser, you can respond to the completed login here


Causes the authentication provider to begin a logout process.
    .then(({state, error}) => {
        // If we don't have to redirect the browser, you can respond to the completed logout here


Causes the authentication provider to refresh an expired token.
    .then(({state, error}) => {
        // If we don't have to redirect the browser, you can respond to the completed refresh here

The providerOptions parameter contains any optional provider-specific options. For example, the Implicit Grant provider lets you specify whether the refresh should be attempted invisibly to the user in an iframe, or visibly in a popup window.
The code is written using ES6 and ES Modules and uses Yarn as the canonical package manager.
Install dependencies with:

To run in-browser tests on all installed, supported browsers:
yarn test

To run a file watch and re-run tests whenever the files change:
yarn watch-test