fix(drawer): drawer container not reacting to drawer removal and mode change

* Fixes the drawer container not reacting if one of the drawers is destroyed.
* Fixes the drawer container not reacting if the mode of a drawer is changed.

Fixes #6271.

Author: crisbeto

src/lib/sidenav/drawer.spec.ts

@@ -312,7 +312,11 @@ describe('MdDrawerContainer', () => {
   beforeEach(async(() => {
     TestBed.configureTestingModule({
       imports: [MdSidenavModule, A11yModule, PlatformModule, NoopAnimationsModule],
-      declarations: [DrawerContainerTwoDrawerTestApp, DrawerDelayed],
+      declarations: [
+        DrawerContainerTwoDrawerTestApp,
+        DrawerDelayed,
+        DrawerContainerStateChangesTestApp,
+      ],
     });
 
     TestBed.compileComponents();
@@ -361,6 +365,47 @@ describe('MdDrawerContainer', () => {
 
     expect(parseInt(contentElement.style.marginLeft)).toBeGreaterThan(0);
   }));
+
+  it('should recalculate the margin if a drawer is destroyed', fakeAsync(() => {
+    const fixture = TestBed.createComponent(DrawerContainerStateChangesTestApp);
+
+    fixture.detectChanges();
+    fixture.componentInstance.drawer.open();
+    fixture.detectChanges();
+    tick();
+    fixture.detectChanges();
+
+    const contentElement = fixture.debugElement.nativeElement.querySelector('.mat-drawer-content');
+    const initialMargin = parseInt(contentElement.style.marginLeft);
+
+    expect(initialMargin).toBeGreaterThan(0);
+
+    fixture.componentInstance.renderDrawer = false;
+    fixture.detectChanges();
+
+    expect(parseInt(contentElement.style.marginLeft)).toBeLessThan(initialMargin);
+  }));
+
+  it('should recalculate the margin if the drawer mode is changed', fakeAsync(() => {
+    const fixture = TestBed.createComponent(DrawerContainerStateChangesTestApp);
+
+    fixture.detectChanges();
+    fixture.componentInstance.drawer.open();
+    fixture.detectChanges();
+    tick();
+    fixture.detectChanges();
+
+    const contentElement = fixture.debugElement.nativeElement.querySelector('.mat-drawer-content');
+    const initialMargin = parseInt(contentElement.style.marginLeft);
+
+    expect(initialMargin).toBeGreaterThan(0);
+
+    fixture.componentInstance.mode = 'over';
+    fixture.detectChanges();
+
+    expect(parseInt(contentElement.style.marginLeft)).toBeLessThan(initialMargin);
+  }));
+
 });
 
 
@@ -472,3 +517,19 @@ class DrawerDelayed {
   @ViewChild(MdDrawer) drawer: MdDrawer;
   showDrawer = false;
 }
+
+
+@Component({
+  template: `
+    <md-drawer-container>
+      <md-drawer *ngIf="renderDrawer" [mode]="mode"></md-drawer>
+    </md-drawer-container>`,
+})
+class DrawerContainerStateChangesTestApp {
+  @ViewChild(MdDrawer) drawer: MdDrawer;
+  @ViewChild(MdDrawerContainer) drawerContainer: MdDrawerContainer;
+
+  mode = 'side';
+  renderDrawer = true;
+}
+

src/lib/sidenav/drawer.ts

@@ -23,6 +23,8 @@ import {
   OnDestroy,
   Inject,
   ChangeDetectorRef,
+  OnChanges,
+  SimpleChanges,
 } from '@angular/core';
 import {animate, state, style, transition, trigger, AnimationEvent} from '@angular/animations';
 import {Directionality, coerceBooleanProperty} from '../core';
@@ -31,7 +33,7 @@ import {ESCAPE} from '../core/keyboard/keycodes';
 import {first, takeUntil, startWith} from '../core/rxjs/index';
 import {DOCUMENT} from '@angular/platform-browser';
 import {merge} from 'rxjs/observable/merge';
-import {Subscription} from 'rxjs/Subscription';
+import {Subject} from 'rxjs/Subject';
 
 
 /** Throws an exception when two MdDrawer are matching the same position. */
@@ -90,7 +92,7 @@ export class MdDrawerToggleResult {
   changeDetection: ChangeDetectionStrategy.OnPush,
   encapsulation: ViewEncapsulation.None,
 })
-export class MdDrawer implements AfterContentInit, OnDestroy {
+export class MdDrawer implements AfterContentInit, OnDestroy, OnChanges {
   private _focusTrap: FocusTrap;
   private _elementFocusedBeforeDrawerWasOpened: HTMLElement | null = null;
 
@@ -153,6 +155,9 @@ export class MdDrawer implements AfterContentInit, OnDestroy {
   /** Event emitted when the drawer's position changes. */
   @Output('positionChanged') onPositionChanged = new EventEmitter<void>();
 
+  /** Event emitted when the drawer's mode changes. */
+  @Output('modeChanged') onModeChanged = new EventEmitter<void>();
+
   /** @deprecated */
   @Output('align-changed') onAlignChanged = new EventEmitter<void>();
 
@@ -206,6 +211,12 @@ export class MdDrawer implements AfterContentInit, OnDestroy {
     }
   }
 
+  ngOnChanges(changes: SimpleChanges) {
+    if (changes.mode) {
+      this.onModeChanged.emit();
+    }
+  }
+
   /**
    * Whether the drawer is opened. We overload this because we trigger an event when it
    * starts or end.
@@ -339,8 +350,8 @@ export class MdDrawerContainer implements AfterContentInit, OnDestroy {
   private _left: MdDrawer | null;
   private _right: MdDrawer | null;
 
-  /** Subscription to the Directionality change EventEmitter. */
-  private _dirChangeSubscription = Subscription.EMPTY;
+  /** Emits when the component is destroyed. */
+  private _onDestroy = new Subject<void>();
 
   /** Inline styles to be applied to the container. */
   _styles: { marginLeft: string; marginRight: string; transform: string; };
@@ -351,22 +362,35 @@ export class MdDrawerContainer implements AfterContentInit, OnDestroy {
     // If a `Dir` directive exists up the tree, listen direction changes and update the left/right
     // properties to point to the proper start/end.
     if (_dir != null) {
-      this._dirChangeSubscription = _dir.change.subscribe(() => this._validateDrawers());
+
+      takeUntil.call(_dir.change, this._onDestroy).subscribe(() => this._validateDrawers());
     }
   }
 
   ngAfterContentInit() {
     startWith.call(this._drawers.changes, null).subscribe(() => {
       this._validateDrawers();
+
       this._drawers.forEach((drawer: MdDrawer) => {
         this._watchDrawerToggle(drawer);
         this._watchDrawerPosition(drawer);
+        this._watchDrawerMode(drawer);
       });
+
+      if (!this._drawers.length ||
+          this._isDrawerOpen(this._start) ||
+          this._isDrawerOpen(this._end)
+      ) {
+        this._updateStyles();
+      }
+
+      this._changeDetectorRef.markForCheck();
     });
   }
 
   ngOnDestroy() {
-    this._dirChangeSubscription.unsubscribe();
+    this._onDestroy.next();
+    this._onDestroy.complete();
   }
 
   /** Calls `open` of both start and end drawers */
@@ -416,6 +440,14 @@ export class MdDrawerContainer implements AfterContentInit, OnDestroy {
     });
   }
 
+  private _watchDrawerMode(drawer: MdDrawer): void {
+    takeUntil.call(drawer.onModeChanged, merge(this._drawers.changes, this._onDestroy))
+      .subscribe(() => {
+        this._updateStyles();
+        this._changeDetectorRef.markForCheck();
+      });
+  }
+
   /** Toggles the 'mat-drawer-opened' class on the main 'md-drawer-container' element. */
   private _setContainerClass(isAdd: boolean): void {
     if (isAdd) {