feat(aio): add progress bar

closes #16110

aio/src/app/app.component.html

@@ -1,3 +1,7 @@
+<div *ngIf="isFetching" class="progress-bar-container">
+  <md-progress-bar mode="indeterminate" color="warn"></md-progress-bar>
+</div>
+
 <md-toolbar color="primary" class="app-toolbar">
   <button class="hamburger" md-button
     (click)="sidenav.toggle()" title="Docs menu">

aio/src/app/app.component.spec.ts

@@ -3,6 +3,7 @@ import { async, inject, ComponentFixture, TestBed, fakeAsync, tick } from '@angu
 import { Title } from '@angular/platform-browser';
 import { APP_BASE_HREF } from '@angular/common';
 import { Http } from '@angular/http';
+import { MdProgressBar } from '@angular/material';
 import { By } from '@angular/platform-browser';
 
 import { BehaviorSubject } from 'rxjs/BehaviorSubject';
@@ -36,18 +37,24 @@ describe('AppComponent', () => {
   let locationService: MockLocationService;
   let sidenav: HTMLElement;
 
-  beforeEach(() => {
-    createTestingModule('a/b');
-
+  const initializeTest = () => {
     fixture = TestBed.createComponent(AppComponent);
     component = fixture.componentInstance;
-    fixture.detectChanges();
 
+    fixture.detectChanges();
     component.onResize(1033); // wide by default
+
     docViewer = fixture.debugElement.query(By.css('aio-doc-viewer')).nativeElement;
     hamburger = fixture.debugElement.query(By.css('.hamburger')).nativeElement;
     locationService = fixture.debugElement.injector.get(LocationService) as any;
     sidenav = fixture.debugElement.query(By.css('md-sidenav')).nativeElement;
+  };
+
+  describe('with proper DocViewer', () => {
+
+    beforeEach(() => {
+      createTestingModule('a/b');
+      initializeTest();
     });
 
     it('should create', () => {
@@ -403,30 +410,6 @@ describe('AppComponent', () => {
       }));
     });
 
-  describe('initial rendering', () => {
-    beforeEach(() => {
-      createTestingModule('a/b');
-      // Remove the DocViewer for this test and hide the missing component message
-      TestBed.overrideModule(AppModule, {
-        remove: { declarations: [DocViewerComponent] },
-        add: { schemas: [NO_ERRORS_SCHEMA] }
-      });
-    });
-
-    it('should initially add the starting class until the first document is rendered', () => {
-      fixture = TestBed.createComponent(AppComponent);
-      fixture.detectChanges();
-
-      expect(fixture.componentInstance.isStarting).toBe(true);
-      expect(fixture.debugElement.query(By.css('md-sidenav-container')).classes['starting']).toBe(true);
-
-      fixture.debugElement.query(By.css('aio-doc-viewer')).triggerEventHandler('docRendered', {});
-      fixture.detectChanges();
-      expect(fixture.componentInstance.isStarting).toBe(false);
-      expect(fixture.debugElement.query(By.css('md-sidenav-container')).classes['starting']).toBe(false);
-    });
-  });
-
     describe('click intercepting', () => {
       it('should intercept clicks on anchors and call `location.handleAnchorClick()`',
               inject([LocationService], (location: LocationService) => {
@@ -581,6 +564,151 @@ describe('AppComponent', () => {
 
   });
 
+  describe('with mocked DocViewer', () => {
+    const getDocViewer = () => fixture.debugElement.query(By.css('aio-doc-viewer'));
+    const triggerDocRendered = () => getDocViewer().triggerEventHandler('docRendered', {});
+
+    beforeEach(() => {
+      createTestingModule('a/b');
+      // Remove the DocViewer for this test and hide the missing component message
+      TestBed.overrideModule(AppModule, {
+        remove: { declarations: [DocViewerComponent] },
+        add: { schemas: [NO_ERRORS_SCHEMA] }
+      });
+    });
+
+    describe('initial rendering', () => {
+      it('should initially add the starting class until the first document is rendered', fakeAsync(() => {
+        const getSidenavContainer = () => fixture.debugElement.query(By.css('md-sidenav-container'));
+
+        initializeTest();
+
+        expect(component.isStarting).toBe(true);
+        expect(getSidenavContainer().classes['starting']).toBe(true);
+
+        triggerDocRendered();
+        fixture.detectChanges();
+        expect(component.isStarting).toBe(true);
+        expect(getSidenavContainer().classes['starting']).toBe(true);
+
+        tick(499);
+        fixture.detectChanges();
+        expect(component.isStarting).toBe(true);
+        expect(getSidenavContainer().classes['starting']).toBe(true);
+
+        tick(2);
+        fixture.detectChanges();
+        expect(component.isStarting).toBe(false);
+        expect(getSidenavContainer().classes['starting']).toBe(false);
+      }));
+    });
+
+    describe('progress bar', () => {
+      const SHOW_DELAY = 200;
+      const HIDE_DELAY = 500;
+      const getProgressBar = () => fixture.debugElement.query(By.directive(MdProgressBar));
+      const initializeAndCompleteNavigation = () => {
+        initializeTest();
+        triggerDocRendered();
+        tick(HIDE_DELAY);
+      };
+
+      it('should initially be hidden', () => {
+        initializeTest();
+        expect(getProgressBar()).toBeFalsy();
+      });
+
+      it('should be shown (after a delay) when the path changes', fakeAsync(() => {
+        initializeAndCompleteNavigation();
+        locationService.urlSubject.next('c/d');
+
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeFalsy();
+
+        tick(SHOW_DELAY - 1);
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeFalsy();
+
+        tick(1);
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeTruthy();
+      }));
+
+      it('should not be shown when the URL changes but the path remains the same', fakeAsync(() => {
+        initializeAndCompleteNavigation();
+        locationService.urlSubject.next('a/b');
+
+        tick(SHOW_DELAY);
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeFalsy();
+      }));
+
+      it('should not be shown if the doc is rendered quickly', fakeAsync(() => {
+        initializeAndCompleteNavigation();
+        locationService.urlSubject.next('c/d');
+
+        tick(SHOW_DELAY - 1);
+        triggerDocRendered();
+
+        tick(1);
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeFalsy();
+
+        tick(HIDE_DELAY);   // Fire the remaining timer or `fakeAsync()` complains.
+      }));
+
+      it('should be shown if rendering the doc takes too long', fakeAsync(() => {
+        initializeAndCompleteNavigation();
+        locationService.urlSubject.next('c/d');
+
+        tick(SHOW_DELAY);
+        triggerDocRendered();
+
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeTruthy();
+
+        tick(HIDE_DELAY);   // Fire the remaining timer or `fakeAsync()` complains.
+      }));
+
+      it('should be hidden (after a delay) once the doc is rendered', fakeAsync(() => {
+        initializeAndCompleteNavigation();
+        locationService.urlSubject.next('c/d');
+
+        tick(SHOW_DELAY);
+        triggerDocRendered();
+
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeTruthy();
+
+        tick(HIDE_DELAY - 1);
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeTruthy();
+
+        tick(1);
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeFalsy();
+      }));
+
+      it('should only take the latest request into account', fakeAsync(() => {
+        initializeAndCompleteNavigation();
+        locationService.urlSubject.next('c/d');   // The URL changes.
+        locationService.urlSubject.next('e/f');   // The URL changes again before `onDocRendered()`.
+
+        tick(SHOW_DELAY - 1);   // `onDocRendered()` is triggered (for the last doc),
+        triggerDocRendered();   // before the progress bar is shown.
+
+        tick(1);
+        fixture.detectChanges();
+        expect(getProgressBar()).toBeFalsy();
+
+        tick(HIDE_DELAY);   // Fire the remaining timer or `fakeAsync()` complains.
+      }));
+    });
+
+  });
+
+});
+
 //// test helpers ////
 
 function createTestingModule(initialUrl: string) {

aio/src/app/app.component.ts

@@ -54,8 +54,10 @@ export class AppComponent implements OnInit {
   @HostBinding('class')
   hostClasses = '';
 
+  isFetching = false;
   isStarting = true;
   isSideBySide = false;
+  private isFetchingTimeout: any;
   private isSideNavDoc = false;
   private previousNavView: string;
 
@@ -122,6 +124,10 @@ export class AppComponent implements OnInit {
       } else {
         // don't scroll; leave that to `onDocRendered`
         this.currentPath = path;
+
+        // Start progress bar if doc not rendered within brief time
+        clearTimeout(this.isFetchingTimeout);
+        this.isFetchingTimeout = setTimeout(() => this.isFetching = true, 200);
       }
     });
 
@@ -168,10 +174,16 @@ export class AppComponent implements OnInit {
   }
 
   onDocRendered() {
+    // Stop fetching timeout (which, when render is fast, means progress bar never shown)
+    clearTimeout(this.isFetchingTimeout);
+
     // Scroll 500ms after the doc-viewer has finished rendering the new doc
     // The delay is to allow time for async layout to complete
-    setTimeout(() => this.autoScroll(), 500);
+    setTimeout(() => {
+      this.autoScroll();
       this.isStarting = false;
+      this.isFetching = false;
+    }, 500);
   }
 
   onDocVersionChange(versionIndex: number) {

aio/src/app/app.module.ts

@@ -5,8 +5,17 @@ import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
 
 import { Location, LocationStrategy, PathLocationStrategy } from '@angular/common';
 
-import { MdToolbarModule, MdButtonModule, MdIconModule, MdInputModule, MdSidenavModule, MdTabsModule, Platform,
-         MdIconRegistry } from '@angular/material';
+import {
+  MdButtonModule,
+  MdIconModule,
+  MdIconRegistry,
+  MdInputModule,
+  MdProgressBarModule,
+  MdSidenavModule,
+  MdTabsModule,
+  MdToolbarModule,
+  Platform
+} from '@angular/material';
 
 // Temporary fix for MdSidenavModule issue:
 // crashes with "missing first" operator when SideNav.mode is "over"
@@ -67,9 +76,10 @@ export const svgIconProviders = [
     MdButtonModule,
     MdIconModule,
     MdInputModule,
-    MdToolbarModule,
+    MdProgressBarModule,
     MdSidenavModule,
     MdTabsModule,
+    MdToolbarModule,
     SwUpdatesModule
   ],
   declarations: [

aio/src/styles/1-layouts/_content-layout.scss

@@ -1,3 +1,12 @@
+.progress-bar-container {
+  height: 2px;
+  overflow: hidden;
+  position: fixed;
+  top: 64px;
+  width: 100vw;
+  z-index: 5;
+}
+
 .sidenav-content {
   padding: 1rem 3rem 3rem;
   margin: auto;
@@ -12,9 +21,15 @@
   aio-menu {
     display: none;
   }
+
+  .progress-bar-container {
+    top: 56px;
+  }
+
   .sidenav-content {
     min-height: 450px;
   }
+
 }
 
 .sidenav-container {