(core) Add viewport meta tag conditionally, and show a toggle for it on small devices.

Summary:
- Enable narrow-screen layout for home page
- Clean up margins/spacing on small-screen home page
- Use "<768" as small-screen condition rather than "<=768".
- Include meta-viewport tag conditionally, off by default.
- Include "Toggle Mobile Mode" option in AccountMenu to toggle it on.
- In a test, add an after() clause to restore window size even when test fails

Test Plan: Only tested manually on iPhone (Safari & FF).

Reviewers: paulfitz

Reviewed By: paulfitz

Subscribers: cyprien

Differential Revision: https://phab.getgrist.com/D2708

app/client/lib/localStorageObs.ts

@@ -1,11 +1,58 @@
 import {Observable} from 'grainjs';
 
+/**
+ * Returns true if storage is functional. In some cass (e.g. when embedded), localStorage may
+ * throw errors. If so, we return false. This implementation is the approach taken by store.js.
+ */
+function testStorage(storage: Storage) {
+  try {
+    const testStr = '__localStorage_test';
+    storage.setItem(testStr, testStr);
+    const ok = (storage.getItem(testStr) === testStr);
+    storage.removeItem(testStr);
+    return ok;
+  } catch (e) {
+    return false;
+  }
+}
+
+/**
+ * Returns localStorage if functional, or sessionStorage, or an in-memory storage. The fallbacks
+ * help with tests, and may help when Grist is embedded.
+ */
+export function getStorage(): Storage {
+  return _storage || (_storage = createStorage());
+}
+
+let _storage: Storage|undefined;
+
+function createStorage(): Storage {
+  if (typeof localStorage !== 'undefined' && testStorage(localStorage)) {
+    return localStorage;
+  }
+  if (typeof sessionStorage !== 'undefined' && testStorage(sessionStorage)) {
+    return sessionStorage;
+  }
+
+  // Fall back to a Map-based implementation of (non-persistent) localStorage.
+  const values = new Map<string, string>();
+  return {
+    setItem(key: string, val: string) { values.set(key, val); },
+    getItem(key: string) { return values.get(key) ?? null; },
+    removeItem(key: string) { values.delete(key); },
+    clear() { values.clear(); },
+    get length() { return values.size; },
+    key(index: number): string|null { throw new Error('Not implemented'); },
+  };
+}
+
 /**
  * Helper to create a boolean observable whose state is stored in localStorage.
  */
 export function localStorageBoolObs(key: string): Observable<boolean> {
-  const obs = Observable.create(null, Boolean(localStorage.getItem(key)));
-  obs.addListener((val) => val ? localStorage.setItem(key, 'true') : localStorage.removeItem(key));
+  const store = getStorage();
+  const obs = Observable.create(null, Boolean(store.getItem(key)));
+  obs.addListener((val) => val ? store.setItem(key, 'true') : store.removeItem(key));
   return obs;
 }
 
@@ -13,7 +60,8 @@ export function localStorageBoolObs(key: string): Observable<boolean> {
  * Helper to create a string observable whose state is stored in localStorage.
  */
 export function localStorageObs(key: string): Observable<string|null> {
-  const obs = Observable.create<string|null>(null, localStorage.getItem(key));
-  obs.addListener((val) => (val === null) ? localStorage.removeItem(key) : localStorage.setItem(key, val));
+  const store = getStorage();
+  const obs = Observable.create<string|null>(null, store.getItem(key));
+  obs.addListener((val) => (val === null) ? store.removeItem(key) : store.setItem(key, val));
   return obs;
 }

app/client/ui/AccountWidget.ts

@@ -5,8 +5,9 @@ import {getLoginOrSignupUrl, getLoginUrl, getLogoutUrl, urlState} from 'app/clie
 import {showDocSettingsModal} from 'app/client/ui/DocumentSettings';
 import {showProfileModal} from 'app/client/ui/ProfileDialog';
 import {createUserImage} from 'app/client/ui/UserImage';
+import * as viewport from 'app/client/ui/viewport';
 import {primaryButtonLink} from 'app/client/ui2018/buttons';
-import {colors, testId, vars} from 'app/client/ui2018/cssVars';
+import {colors, mediaDeviceNotSmall, testId, vars} from 'app/client/ui2018/cssVars';
 import {icon} from 'app/client/ui2018/icons';
 import {menu, menuDivider, menuItem, menuItemLink, menuSubHeader} from 'app/client/ui2018/menus';
 import {commonUrls} from 'app/common/gristUrls';
@@ -111,6 +112,13 @@ export class AccountWidget extends Disposable {
         ) :
         menuItemLink({href: commonUrls.plans}, 'Upgrade Plan'),
 
+      menuItem(viewport.toggleViewport,
+        cssSmallDeviceOnly.cls(''),   // Only show this toggle on small devices.
+        'Toggle Mobile Mode',
+        cssCheckmark('Tick', dom.show(viewport.viewportEnabled)),
+        testId('usermenu-toggle-mobile'),
+      ),
+
       // TODO Add section ("Here right now") listing icons of other users currently on this doc.
       // (See Invision "Panels" near the bottom.)
 
@@ -222,3 +230,19 @@ const cssOrgCheckmark = styled(icon, `
     display: block;
   }
 `);
+
+const cssCheckmark = styled(icon, `
+  flex: none;
+  margin-left: 16px;
+  --icon-color: ${colors.lightGreen};
+`);
+
+// Note that this css class hides the item when the device width is small (not based on viewport
+// width, which may be larger). This only appropriate for when to enable the "mobile mode" toggle.
+const cssSmallDeviceOnly = styled(menuItem, `
+  @media ${mediaDeviceNotSmall} {
+    & {
+      display: none;
+    }
+  }
+`);

app/client/ui/App.ts

@@ -10,6 +10,7 @@ import * as koUtil from 'app/client/lib/koUtil';
 import {reportError, TopAppModel, TopAppModelImpl} from 'app/client/models/AppModel';
 import {setUpErrorHandling} from 'app/client/models/errors';
 import {createAppUI} from 'app/client/ui/AppUI';
+import {addViewportTag} from 'app/client/ui/viewport';
 import {attachCssRootVars} from 'app/client/ui2018/cssVars';
 import {BaseAPI} from 'app/common/BaseAPI';
 import {DisposableWithEvents} from 'app/common/DisposableWithEvents';
@@ -154,6 +155,7 @@ export class App extends DisposableWithEvents {
 
     // Add the cssRootVars class to enable the variables in cssVars.
     attachCssRootVars(this.topAppModel.productFlavor);
+    addViewportTag();
     this.autoDispose(createAppUI(this.topAppModel, this));
   }
 

app/client/ui/AppUI.ts

@@ -100,6 +100,7 @@ function pagePanelsHome(owner: IDisposableOwner, appModel: AppModel) {
     },
     headerMain: createTopBarHome(appModel),
     contentMain: createDocMenu(pageModel),
+    optimizeNarrowScreen: true,
   });
 }
 

app/client/ui/DocMenuCss.ts

@@ -1,5 +1,5 @@
 import {transientInput} from 'app/client/ui/transientInput';
-import {colors, vars} from 'app/client/ui2018/cssVars';
+import {colors, mediaSmall, vars} from 'app/client/ui2018/cssVars';
 import {icon} from 'app/client/ui2018/icons';
 import {styled} from 'grainjs';
 
@@ -15,6 +15,11 @@ export const docList = styled('div', `
     display: block;
     height: 64px;
   }
+  @media ${mediaSmall} {
+    & {
+      padding: 32px 24px 24px 24px;
+    }
+  }
 `);
 
 export const docListHeader = styled('div', `
@@ -216,6 +221,12 @@ export const prefSelectors = styled('div', `
   right: 64px;
   display: flex;
   align-items: center;
+
+  @media ${mediaSmall} {
+    & {
+      right: 24px;
+    }
+  }
 `);
 
 export const sortSelector = styled('div', `
@@ -236,4 +247,9 @@ export const sortSelector = styled('div', `
     box-shadow: none;
     background-color: ${colors.mediumGrey};
   }
+  @media ${mediaSmall} {
+    & {
+      margin-right: 0;
+    }
+  }
 `);

app/client/ui/PagePanels.ts

@@ -3,7 +3,7 @@
  */
 import {resizeFlexVHandle} from 'app/client/ui/resizeHandle';
 import {transition} from 'app/client/ui/transitions';
-import {colors, cssHideForNarrowScreen, maxNarrowScreenWidth} from 'app/client/ui2018/cssVars';
+import {colors, cssHideForNarrowScreen, mediaNotSmall, mediaSmall} from 'app/client/ui2018/cssVars';
 import {icon} from 'app/client/ui2018/icons';
 import {dom, DomArg, noTestId, Observable, styled, TestId} from "grainjs";
 
@@ -39,7 +39,6 @@ export function pagePanels(page: PageContents) {
 
   return [cssPageContainer(
     cssPageContainer.cls('-optimizeNarrowScreen', optimizeNarrowScreen),
-    optimizeNarrowScreen ? dom.style('min-width', '240px') : null,
     cssLeftPane(
       testId('left-panel'),
       cssTopHeader(left.header),
@@ -121,39 +120,36 @@ export function pagePanels(page: PageContents) {
         left.panelOpen.set(false);
         if (right) { right.panelOpen.set(false); }
       }),
-      testId('overlay'))
+      testId('overlay')
+    ),
   ), (
     !optimizeNarrowScreen ? null :
       cssBottomFooter(
         testId('bottom-footer'),
-        (left.hideOpener ? null :
-         cssPanelOpenerNarrowScreenBtn(
-           cssPanelOpenerNarrowScreen(
-             'FieldTextbox',
-             dom.on('click', () => {
-               if (right) {
-                 right.panelOpen.set(false);
-               }
-               toggleObs(left.panelOpen);
-             }),
-             testId('left-opener-ns')
-           ),
-           cssPanelOpenerNarrowScreenBtn.cls('-open', left.panelOpen)
-         )
+        cssPanelOpenerNarrowScreenBtn(
+          cssPanelOpenerNarrowScreen(
+            'FieldTextbox',
+            dom.on('click', () => {
+              right?.panelOpen.set(false);
+              toggleObs(left.panelOpen);
+            }),
+            testId('left-opener-ns')
+          ),
+          cssPanelOpenerNarrowScreenBtn.cls('-open', left.panelOpen)
         ),
         page.contentBottom,
-        (!right || right.hideOpener ? null :
-         cssPanelOpenerNarrowScreenBtn(
-           cssPanelOpenerNarrowScreen(
-             'Settings',
-             dom.on('click', () => {
-               left.panelOpen.set(false);
-               toggleObs(right.panelOpen);
-             }),
-             testId('right-opener-ns')
-           ),
-           cssPanelOpenerNarrowScreenBtn.cls('-open', right.panelOpen),
-         )
+        (!right ? null :
+          cssPanelOpenerNarrowScreenBtn(
+            cssPanelOpenerNarrowScreen(
+              'Settings',
+              dom.on('click', () => {
+                left.panelOpen.set(false);
+                toggleObs(right.panelOpen);
+              }),
+              testId('right-opener-ns')
+            ),
+            cssPanelOpenerNarrowScreenBtn.cls('-open', right.panelOpen),
+          )
         ),
       )
   )];
@@ -178,15 +174,15 @@ const cssPageContainer = styled(cssHBox, `
   left: 0;
   right: 0;
   bottom: 0;
-  min-width: 600px
+  min-width: 600px;
   background-color: ${colors.lightGrey};
 
-  @media (max-width: ${maxNarrowScreenWidth}px) {
+  @media ${mediaSmall} {
     &-optimizeNarrowScreen {
       bottom: 48px;
+      min-width: 240px;
     }
   }
-
 `);
 export const cssLeftPane = styled(cssVBox, `
   position: relative;
@@ -195,7 +191,7 @@ export const cssLeftPane = styled(cssVBox, `
   margin-right: 0px;
   overflow: hidden;
   transition: margin-right 0.4s;
-  @media (max-width: ${maxNarrowScreenWidth}px) {
+  @media ${mediaSmall} {
     .${cssPageContainer.className}-optimizeNarrowScreen & {
       width: 0px;
       position: absolute;
@@ -204,7 +200,6 @@ export const cssLeftPane = styled(cssVBox, `
       bottom: 0;
       left: 0;
       box-shadow: 10px 0 5px rgba(0, 0, 0, 0.2);
-      border-bottom: 1px solid ${colors.mediumGrey};
     }
   }
   &-open {
@@ -236,7 +231,7 @@ const cssRightPane = styled(cssVBox, `
   overflow: hidden;
   transition: margin-left 0.4s;
   z-index: 0;
-  @media (max-width: ${maxNarrowScreenWidth}px) {
+  @media ${mediaSmall} {
     .${cssPageContainer.className}-optimizeNarrowScreen & {
       position: absolute;
       z-index: 10;
@@ -244,7 +239,6 @@ const cssRightPane = styled(cssVBox, `
       bottom: 0;
       right: 0;
       box-shadow: -10px 0 5px rgba(0, 0, 0, 0.2);
-      border-bottom: 1px solid ${colors.mediumGrey};
     }
   }
   &-open {
@@ -292,7 +286,8 @@ const cssBottomFooter = styled ('div', `
   bottom: 0;
   left: 0;
   right: 0;
-  @media not all and (max-width: ${maxNarrowScreenWidth}px) {
+  border-top: 1px solid ${colors.mediumGrey};
+  @media ${mediaNotSmall} {
     & {
       display: none;
     }
@@ -352,7 +347,7 @@ const cssContentOverlay = styled('div', `
   opacity: 0.5;
   display: none;
   z-index: 9;
-  @media (max-width: ${maxNarrowScreenWidth}px) {
+  @media ${mediaSmall} {
     .${cssPageContainer.className}-optimizeNarrowScreen & {
       display: unset;
     }

app/client/ui/viewport.ts

@@ -0,0 +1,20 @@
+import {localStorageBoolObs} from 'app/client/lib/localStorageObs';
+import {dom} from 'grainjs';
+
+export const viewportEnabled = localStorageBoolObs('viewportEnabled');
+
+export function toggleViewport() {
+  viewportEnabled.set(!viewportEnabled.get());
+  if (!viewportEnabled.get()) {
+    // Removing the meta tag doesn't cause mobile browsers to reload automatically.
+    location.reload();
+  }
+}
+
+export function addViewportTag() {
+  dom.update(document.head,
+    dom.maybe(viewportEnabled, () =>
+      dom('meta', {name: "viewport", content: "width=device-width,initial-scale=1.0"})
+    )
+  );
+}

app/client/ui2018/breadcrumbs.ts

@@ -6,7 +6,7 @@
  * Workspace is a clickable link and document and page names are editable labels.
  */
 import { urlState } from 'app/client/models/gristUrlState';
-import { colors, cssHideForNarrowScreen, maxNarrowScreenWidth, testId } from 'app/client/ui2018/cssVars';
+import { colors, cssHideForNarrowScreen, mediaNotSmall, testId } from 'app/client/ui2018/cssVars';
 import { editableLabel } from 'app/client/ui2018/editableLabel';
 import { icon } from 'app/client/ui2018/icons';
 import { UserOverride } from 'app/common/DocListAPI';
@@ -55,7 +55,7 @@ const cssWorkspaceNarrowScreen = styled(icon, `
   margin-right: 8px;
   background-color: ${colors.slate};
   cursor: pointer;
-  @media not all and (max-width: ${maxNarrowScreenWidth}px) {
+  @media ${mediaNotSmall} {
     & {
       display: none;
     }

app/client/ui2018/cssVars.ts

@@ -154,15 +154,22 @@ export const cssRootVars = cssBodyVars.className;
 // class ".test-{name}". Ideally, we'd use noTestId() instead in production.
 export const testId: TestId = makeTestId('test-');
 
-// Max width for narrow screen layout (in px). Note: 768px is bootstrap's definition of small screen
-export const maxNarrowScreenWidth = 768;
+// Min width for normal screen layout (in px). Note: <768px is bootstrap's definition of small
+// screen (covers phones, including landscape, but not tablets).
+const mediumScreenWidth = 768;
+
+// Fractional width for max-query follows https://getbootstrap.com/docs/4.0/layout/overview/#responsive-breakpoints
+export const mediaSmall = `(max-width: ${mediumScreenWidth - 0.02}px)`;
+export const mediaNotSmall = `(min-width: ${mediumScreenWidth}px)`;
+
+export const mediaDeviceNotSmall = `(min-device-width: ${mediumScreenWidth}px)`;
 
 export function isNarrowScreen() {
   return window.innerWidth <= 768;
 }
 
 export const cssHideForNarrowScreen = styled('div', `
-  @media (max-width: ${maxNarrowScreenWidth}px) {
+  @media ${mediaSmall} {
     & {
       display: none !important;
     }