[SDK-1386] Fall back to iframe method if no refresh token is available

__tests__/index.test.ts

@@ -1442,26 +1442,6 @@ describe('Auth0', () => {
             }
           });
         });
-
-        it('fails with an error when no refresh token is available in the cache', async () => {
-          const { auth0, cache, utils } = await setup({
-            useRefreshTokens: true
-          });
-
-          utils.getUniqueScopes.mockReturnValue(
-            `${TEST_SCOPES} offline_access`
-          );
-
-          cache.get.mockReturnValue({ access_token: TEST_ACCESS_TOKEN });
-
-          await auth0.getTokenSilently({ ignoreCache: true }).catch(e => {
-            expect(e.error).toBe('missing_refresh_token');
-            expect(e.error_description).toBe(
-              'No refresh token is available to fetch a new access token. The user should be reauthenticated.'
-            );
-            expect(utils.oauthToken).not.toHaveBeenCalled();
-          });
-        });
       });
     });
 
@@ -1736,6 +1716,23 @@ describe('Auth0', () => {
         );
       });
     });
+
+    describe('when refresh tokens are used', () => {
+      it('falls back to using a hidden iframe when no refresh token is available', async () => {
+        const { auth0, cache, utils } = await setup({
+          useRefreshTokens: true
+        });
+
+        utils.getUniqueScopes.mockReturnValue(`${TEST_SCOPES} offline_access`);
+
+        cache.get.mockReturnValue({ access_token: TEST_ACCESS_TOKEN });
+
+        const result = await auth0.getTokenSilently({ ignoreCache: true });
+
+        expect(result).toEqual(TEST_ACCESS_TOKEN);
+        expect(utils.runIframe).toHaveBeenCalled();
+      });
+    });
   });
 
   describe('getTokenWithPopup()', async () => {

cypress/integration/getTokenSilently.js

@@ -1,11 +1,4 @@
-import { decode } from 'qss';
-import {
-  shouldBe,
-  shouldNotBe,
-  shouldBeUndefined,
-  shouldNotBeUndefined,
-  whenReady
-} from '../support/utils';
+import { shouldBe, whenReady } from '../support/utils';
 
 describe('getTokenSilently', function() {
   beforeEach(cy.resetTests);
@@ -76,7 +69,11 @@ describe('getTokenSilently', function() {
       });
 
       describe('when using refresh tokens', () => {
-        it('displays an error when trying to get an access token when the RT is missing', () => {
+        /**
+         * This test will fail with a 'consent_required' error when running on localhost, but the fact that it does
+         * proves that the iframe method was attempted even though we're supposed to be using refresh tokens.
+         */
+        it.only('attempts to retrieve an access token by falling back to the iframe method', () => {
           return whenReady().then(win => {
             cy.toggleSwitch('local-storage');
             cy.toggleSwitch('use-cache');
@@ -87,12 +84,11 @@ describe('getTokenSilently', function() {
 
               cy.get('[data-cy=get-token]')
                 .click()
-                .wait(500);
+                .wait(500)
+                .get('[data-cy=access-token]')
+                .should('have.length', 1);
 
-              cy.get('[data-cy=error]').should(
-                'contain',
-                'No refresh token is available to fetch a new access token'
-              );
+              cy.get('[data-cy=error]').should('contain', 'consent_required');
             });
           });
         });

src/Auth0Client.ts

@@ -439,7 +439,7 @@ export default class Auth0Client {
    * @param options
    */
   public async getTokenSilently(options: GetTokenSilentlyOptions = {}) {
-    const { ignoreCache, ...refreshTokenOptions } = {
+    const { ignoreCache, ...getTokenOptions } = {
       audience: this.options.audience,
       scope: getUniqueScopes(
         this.DEFAULT_SCOPE,
@@ -453,8 +453,8 @@ export default class Auth0Client {
     try {
       if (!ignoreCache) {
         const cache = this.cache.get({
-          scope: refreshTokenOptions.scope,
-          audience: refreshTokenOptions.audience || 'default',
+          scope: getTokenOptions.scope,
+          audience: getTokenOptions.audience || 'default',
           client_id: this.options.client_id
         });
 
@@ -466,8 +466,8 @@ export default class Auth0Client {
       await lock.acquireLock(GET_TOKEN_SILENTLY_LOCK_KEY, 5000);
 
       const authResult = this.options.useRefreshTokens
-        ? await this._getTokenUsingRefreshToken(refreshTokenOptions)
-        : await this._getTokenFromIFrame(refreshTokenOptions);
+        ? await this._getTokenUsingRefreshToken(getTokenOptions)
+        : await this._getTokenFromIFrame(getTokenOptions);
 
       this.cache.save({ client_id: this.options.client_id, ...authResult });
 
@@ -625,10 +625,7 @@ export default class Auth0Client {
     });
 
     if (!cache || !cache.refresh_token) {
-      throw new GenericError(
-        'missing_refresh_token',
-        'No refresh token is available to fetch a new access token. The user should be reauthenticated.'
-      );
+      return await this._getTokenFromIFrame(options);
     }
 
     const redirect_uri =