Add `authDomain` to `session` store

src/sidebar/store/modules/session.js

@@ -23,8 +23,16 @@ const initialProfile = {
   userid: null,
 };
 
-function init() {
+function init(settings) {
   return {
+    /**
+     * The app's authentication domain, from settings
+     * FIXME: This returns an empty string when `authDomain` is missing
+     * because other app logic has long assumed its string-y presence:
+     * behavior when it's missing is undefined. This setting should be
+     * enforced similarly to how `apiUrl` is enforced.
+     */
+    authDomain: settings?.authDomain ?? '',
     /**
      * Profile object fetched from the `/api/profile` endpoint.
      */
@@ -52,6 +60,14 @@ function updateProfile(profile) {
   };
 }
 
+/**
+ *
+ * @returns {string}
+ */
+function authDomain(state) {
+  return state.authDomain;
+}
+
 /**
  * Return true if a user is logged in and false otherwise.
  *
@@ -103,6 +119,7 @@ export default storeModule({
   },
 
   selectors: {
+    authDomain,
     hasFetchedProfile,
     isFeatureEnabled,
     isLoggedIn,

src/sidebar/store/modules/test/groups-test.js

@@ -71,7 +71,9 @@ describe('sidebar/store/modules/groups', () => {
   let store;
 
   beforeEach(() => {
-    store = createStore([groups, session]);
+    // The empty second argument (settings) needed here because of the
+    // dependency on the `session` module
+    store = createStore([groups, session], [{}]);
   });
 
   describe('focusGroup', () => {

src/sidebar/store/modules/test/session-test.js

 import createStore from '../../create-store';
 import session from '../session';
 
-describe('sidebar/store/modules/session', function () {
+describe('sidebar/store/modules/session', () => {
+  let fakeSettings;
   let store;
 
   beforeEach(() => {
-    store = createStore([session]);
+    fakeSettings = {};
+    store = createStore([session], [fakeSettings]);
   });
 
-  describe('#updateProfile', function () {
-    it('updates the profile data', function () {
+  describe('#updateProfile', () => {
+    it('updates the profile data', () => {
       const newProfile = Object.assign({ userid: 'john' });
       store.updateProfile({ userid: 'john' });
       assert.deepEqual(store.profile(), newProfile);
     });
   });
 
+  describe('#authDomain', () => {
+    it('returns the authDomain from the settings', () => {
+      fakeSettings.authDomain = 'foo.com';
+      store = createStore([session], [fakeSettings]);
+
+      assert.equal(store.authDomain(), 'foo.com');
+    });
+  });
+
   describe('#isLoggedIn', () => {
     [
       { userid: 'john', expectedIsLoggedIn: true },