(core) Reopen HelpScout beacon to the last-opened article

Summary:
- When opening HelpScout beacon to an article ("answers"), avoid a 'navigate'
  call to let the beacon show the previously open article.
- Work around a bug with reloading a page with a beacon article open: HelpScout
  renders the last state without triggering usual events.
- Report errors to server when beacon fails to load.
- reportWarning() method now reports the message to the server.

Test Plan: Added a test case

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D3345

app/client/lib/helpScout.ts

@@ -15,7 +15,8 @@
 
 // tslint:disable:unified-signatures
 
-import {AppModel, reportError} from 'app/client/models/AppModel';
+import {AppModel} from 'app/client/models/AppModel';
+import {reportWarning} from 'app/client/models/errors';
 import {IAppError} from 'app/client/models/NotifyModel';
 import {GristLoadConfig} from 'app/common/gristUrls';
 import {timeFormat} from 'app/common/timeFormat';
@@ -64,7 +65,8 @@ export function Beacon(method: 'navigate', route: string): void;
 export function Beacon(method: 'identify', userObj: IUserObj): void;
 export function Beacon(method: 'prefill', formObj: IFormObj): void;
 export function Beacon(method: 'config', configObj: object): void;
-export function Beacon(method: 'on'|'off'|'once', event: 'open'|'close', callback: () => void): void;
+export function Beacon(method: 'on'|'once', event: string, callback: () => void): void;
+export function Beacon(method: 'off', event: string, callback?: () => void): void;
 export function Beacon(method: 'session-data', data: ISessionData): void;
 export function Beacon(method: BeaconCmd): void;
 export function Beacon(method: BeaconCmd, options?: unknown, data?: unknown) {
@@ -85,21 +87,30 @@ function initBeacon(): void {
     const beaconId = gristConfig && gristConfig.helpScoutBeaconId;
     if (beaconId) {
       (window as any).Beacon = _beacon;
-      document.head.appendChild(dom('script', {
+      document.head.appendChild(dom('script',
+        {
           type: 'text/javascript',
           src: 'https://beacon-v2.helpscout.net',
           async: true,
-      }));
+        },
+        // Report when the beacon fails to load so that the user knows something is wrong, and we
+        // have a log of the error. (Note: might not report all failures due to ad-blockers.)
+        dom.on('error', (e) => {
+          reportWarning("Support form failed to load. " +
+            "Please email support@getgrist.com with questions instead.");
+        }),
+      ));
       _beacon('init', beaconId);
       _beacon('config', {display: {style: "manual"}});
     } else {
       (window as any).Beacon = () => null;
-      reportError(new Error("Support form is not configured"));
+      reportWarning("Support form is not configured");
     }
   }
 }
 
 let lastOpenType: 'error' | 'message' = 'message';
+let lastRoute: BeaconRoute|null = null;
 
 /**
  * Helper to open a beacon, taking care of setting focus appropriately. Calls optional onOpen
@@ -118,31 +129,33 @@ function _beaconOpen(userObj: IUserObj|null, options: IBeaconOpenOptions) {
     lastOpenType = openType;
   }
 
+  const route: BeaconRoute = options.route || (errors?.length ? '/ask/message/' : '/answers/');
+  // If beacon was and still is being opened for help articles, avoid the 'navigate' call
+  // altogether, to keep the beacon at the last article it was on.
+  const skipNav = (route === lastRoute && route === '/answers/');
+  lastRoute = route;
+
   Beacon('once', 'open', () => {
     const iframe = document.querySelector('#beacon-container iframe') as HTMLIFrameElement;
     if (iframe) { iframe.focus(); }
     if (onOpen) { onOpen(); }
   });
-  Beacon('once', 'article-viewed' as any, () => {
-    // HelpScout creates an iframe with an empty 'src' attribute, then writes to it. In such an
-    // iframe, different browsers interpret relative links differently: Chrome's are relative to
-    // the parent page's URL; Firefox's are relative to the parent page's <base href>.
-    //
-    // Here we set a <base href> explicitly in the iframe to get consistent behavior of links
-    // relative to the top page's URL (HelpScout then seems to handle clicks on them correctly).
-    const iframe = document.querySelector('#beacon-container iframe') as HTMLIFrameElement;
-    iframe?.contentDocument?.head.appendChild(dom('base', {href: ''}));
-  });
+  // Fix base-href tag when opening an article.
+  Beacon('once', 'article-viewed', () => fixBeaconBaseHref());
+  // We duplicate this check for 'ready' event, because 'open' and 'article-viewed' events don't
+  // trigger on page reload when a beacon article is already open (seems to be a HelpScout bug).
+  Beacon('once', 'ready', () => fixBeaconBaseHref());
+
   Beacon('once', 'close', () => {
     const iframe = document.querySelector('#beacon-container iframe') as HTMLIFrameElement;
     if (iframe) { iframe.blur(); }
+    Beacon('off', 'article-viewed');
   });
   if (userObj) {
     Beacon('identify', userObj);
   }
 
   const attrs: ISessionData = {};
-  let route: BeaconRoute;
   if (errors?.length) {
     // If sending errors, prefill part of the message (the user sees this and can add to it), and
     // include more detailed errors with stack traces into session-data.
@@ -162,10 +175,8 @@ function _beaconOpen(userObj: IUserObj|null, options: IBeaconOpenOptions) {
         attrs[`error-${i}-stack`] = JSON.stringify(error.stack.trim().split('\n'));
       }
     });
-    route = options.route || '/ask/message/';
   } else {
     Beacon('config', {messaging: {contactForm: {showSubject: true}}});
-    route = options.route || '/answers/';
   }
 
   Beacon('session-data', {
@@ -173,8 +184,24 @@ function _beaconOpen(userObj: IUserObj|null, options: IBeaconOpenOptions) {
     ...attrs,
   });
   Beacon('open');
+  if (!skipNav) {
     Beacon('navigate', route);
   }
+}
+
+function fixBeaconBaseHref() {
+  // HelpScout creates an iframe with an empty 'src' attribute, then writes to it. In such an
+  // iframe, different browsers interpret relative links differently: Chrome's are relative to
+  // the parent page's URL; Firefox's are relative to the parent page's <base href>.
+  //
+  // Here we set a <base href> explicitly in the iframe to get consistent behavior of links
+  // relative to the top page's URL (HelpScout then seems to handle clicks on them correctly).
+  const iframe = document.querySelector('#beacon-container iframe') as HTMLIFrameElement;
+  const iframeDoc = iframe?.contentDocument;
+  if (iframeDoc && !iframeDoc.querySelector('head > base')) {
+    iframeDoc.head.appendChild(dom('base', {href: ''}));
+  }
+}
 
 export interface IBeaconOpenOptions {
   appModel: AppModel|null;

app/client/models/errors.ts

@@ -53,10 +53,14 @@ export function reportMessage(msg: string, options?: Partial<INotifyOptions>) {
 }
 
 /**
- * Shows warning toast notification (with yellow styling).
+ * Shows warning toast notification (with yellow styling), and log to server and to console. Pass
+ * {level: 'error'} for same behavior with adjusted styling.
  */
 export function reportWarning(msg: string, options?: Partial<INotifyOptions>) {
-  reportMessage(msg, {level: 'warning', ...options});
+  options = {level: 'warning', ...options};
+  log.warn(`${options.level}: `, msg);
+  _logError(msg);
+  reportMessage(msg, options);
 }
 
 /**