fix(sidenav): container not reacting to changes to sidenavs added after init

Fixes the sidenav container not reacting to sidenavs that were added after initialization.

Fixes #6127.

Author: crisbeto

src/lib/sidenav/sidenav.spec.ts

@@ -459,9 +459,7 @@ describe('MdSidenavContainer', () => {
   beforeEach(async(() => {
     TestBed.configureTestingModule({
       imports: [MdSidenavModule, A11yModule, PlatformModule],
-      declarations: [
-        SidenavContainerTwoSidenavTestApp
-      ],
+      declarations: [SidenavContainerTwoSidenavTestApp, SidenavDelayed],
     });
 
     TestBed.compileComponents();
@@ -490,6 +488,23 @@ describe('MdSidenavContainer', () => {
         });
     }));
   });
+
+  it('should animate the content when a sidenav is added at a later point', () => {
+    const fixture = TestBed.createComponent(SidenavDelayed);
+
+    fixture.detectChanges();
+
+    const contentElement = fixture.debugElement.nativeElement.querySelector('.mat-sidenav-content');
+
+    expect(parseInt(contentElement.style.marginLeft)).toBe(0);
+
+    fixture.componentInstance.showSidenav = true;
+    fixture.detectChanges();
+    fixture.componentInstance.sidenav.open();
+    fixture.detectChanges();
+
+    expect(parseInt(contentElement.style.marginLeft)).toBeGreaterThan(0);
+  });
 });
 
 
@@ -506,8 +521,7 @@ class SidenavContainerNoSidenavTestApp { }
     </md-sidenav-container>`,
 })
 class SidenavContainerTwoSidenavTestApp {
-  @ViewChild(MdSidenavContainer)
-  sidenavContainer: MdSidenavContainer;
+  @ViewChild(MdSidenavContainer) sidenavContainer: MdSidenavContainer;
 }
 
 /** Test component that contains an MdSidenavContainer and one MdSidenav. */
@@ -601,3 +615,16 @@ class SidenavDynamicAlign {
 class SidenavWitFocusableElements {
   mode: string = 'over';
 }
+
+
+@Component({
+  template: `
+    <md-sidenav-container>
+      <md-sidenav *ngIf="showSidenav" #sidenav mode="side">Sidenav</md-sidenav>
+    </md-sidenav-container>
+  `,
+})
+class SidenavDelayed {
+  @ViewChild(MdSidenav) sidenav: MdSidenav;
+  showSidenav = false;
+}

src/lib/sidenav/sidenav.ts

@@ -27,7 +27,7 @@ import {
 import {Directionality, coerceBooleanProperty} from '../core';
 import {FocusTrapFactory, FocusTrap} from '../core/a11y/focus-trap';
 import {ESCAPE} from '../core/keyboard/keycodes';
-import {first} from '../core/rxjs/index';
+import {first, takeUntil, startWith} from '../core/rxjs/index';
 import {DOCUMENT} from '@angular/platform-browser';
 import {merge} from 'rxjs/observable/merge';
 
@@ -372,13 +372,13 @@ export class MdSidenavContainer implements AfterContentInit {
   }
 
   ngAfterContentInit() {
-    // On changes, assert on consistency.
-    this._sidenavs.changes.subscribe(() => this._validateDrawers());
-    this._sidenavs.forEach((sidenav: MdSidenav) => {
-      this._watchSidenavToggle(sidenav);
-      this._watchSidenavAlign(sidenav);
+    startWith.call(this._sidenavs.changes, null).subscribe(() => {
+      this._validateDrawers();
+      this._sidenavs.forEach((sidenav: MdSidenav) => {
+        this._watchSidenavToggle(sidenav);
+        this._watchSidenavAlign(sidenav);
+      });
     });
-    this._validateDrawers();
   }
 
   /** Calls `open` of both start and end sidenavs */
@@ -401,16 +401,17 @@ export class MdSidenavContainer implements AfterContentInit {
    * is properly hidden.
    */
   private _watchSidenavToggle(sidenav: MdSidenav): void {
-    merge(sidenav.onOpenStart, sidenav.onCloseStart).subscribe(() => {
-      // Set the transition class on the container so that the animations occur. This should not
-      // be set initially because animations should only be triggered via a change in state.
-      this._renderer.addClass(this._element.nativeElement, 'mat-sidenav-transition');
-      this._changeDetectorRef.markForCheck();
-    });
+    takeUntil.call(merge(sidenav.onOpenStart, sidenav.onCloseStart), this._sidenavs.changes)
+      .subscribe(() => {
+        // Set the transition class on the container so that the animations occur. This should not
+        // be set initially because animations should only be triggered via a change in state.
+        this._renderer.addClass(this._element.nativeElement, 'mat-sidenav-transition');
+        this._changeDetectorRef.markForCheck();
+      });
 
     if (sidenav.mode !== 'side') {
-      sidenav.onOpen.subscribe(() => this._setContainerClass(true));
-      sidenav.onClose.subscribe(() => this._setContainerClass(false));
+      takeUntil.call(merge(sidenav.onOpen, sidenav.onClose), this._sidenavs.changes).subscribe(() =>
+          this._setContainerClass(sidenav.opened));
     }
   }
 
@@ -424,7 +425,7 @@ export class MdSidenavContainer implements AfterContentInit {
     }
     // NOTE: We need to wait for the microtask queue to be empty before validating,
     // since both drawers may be swapping sides at the same time.
-    sidenav.onAlignChanged.subscribe(() =>
+    takeUntil.call(sidenav.onAlignChanged, this._sidenavs.changes).subscribe(() =>
         first.call(this._ngZone.onMicrotaskEmpty).subscribe(() => this._validateDrawers()));
   }