feat(snack-bar): add injection token for overriding the default options

src/lib/snack-bar/snack-bar-module.ts

@@ -13,11 +13,17 @@ import {PortalModule} from '@angular/cdk/portal';
 import {LIVE_ANNOUNCER_PROVIDER} from '@angular/cdk/a11y';
 import {LayoutModule} from '@angular/cdk/layout';
 import {MatCommonModule} from '@angular/material/core';
-import {MatSnackBar} from './snack-bar';
+import {MatSnackBar, MAT_SNACK_BAR_DEFAULT_OPTIONS} from './snack-bar';
 import {MatSnackBarContainer} from './snack-bar-container';
+import {MatSnackBarConfig} from './snack-bar-config';
 import {SimpleSnackBar} from './simple-snack-bar';
 
 
+/** @docs-private */
+export function MAT_SNACK_BAR_DEFAULT_OPTIONS_PROVIDER_FACTORY() {
+  return new MatSnackBarConfig();
+}
+
 @NgModule({
   imports: [
     OverlayModule,
@@ -29,6 +35,13 @@ import {SimpleSnackBar} from './simple-snack-bar';
   exports: [MatSnackBarContainer, MatCommonModule],
   declarations: [MatSnackBarContainer, SimpleSnackBar],
   entryComponents: [MatSnackBarContainer, SimpleSnackBar],
-  providers: [MatSnackBar, LIVE_ANNOUNCER_PROVIDER]
+  providers: [
+    MatSnackBar,
+    LIVE_ANNOUNCER_PROVIDER,
+    {
+      provide: MAT_SNACK_BAR_DEFAULT_OPTIONS,
+      useFactory: MAT_SNACK_BAR_DEFAULT_OPTIONS_PROVIDER_FACTORY
+    },
+  ]
 })
 export class MatSnackBarModule {}

src/lib/snack-bar/snack-bar.md

@@ -72,6 +72,19 @@ export class MessageArchivedComponent {
   constructor(@Inject(MAT_SNACK_BAR_DATA) public data: any) { }
 }
 ```
+
+### Setting the global configuration defaults
+If you want to override the default snack bar options, you can do so using the
+`MAT_SNACK_BAR_DEFAULT_OPTIONS` injection token.
+
+```ts
+@NgModule({
+  providers: [
+    {provide: MAT_SNACK_BAR_DEFAULT_OPTIONS, useValue: {duration: 2500}}
+  ]
+})
+```
+
 ### Accessibility
 Snack-bar messages are announced via an `aria-live` region. Focus is not moved to
 the snack-bar element, as this would be disruptive to a user in the middle of a

src/lib/snack-bar/snack-bar.spec.ts

@@ -18,6 +18,7 @@ import {
   MatSnackBarRef,
   SimpleSnackBar,
   MAT_SNACK_BAR_DATA,
+  MAT_SNACK_BAR_DEFAULT_OPTIONS,
 } from './index';
 
 describe('MatSnackBar', () => {
@@ -387,6 +388,32 @@ describe('MatSnackBar', () => {
     expect(pane.getAttribute('dir')).toBe('rtl', 'Expected the pane to be in RTL mode.');
   });
 
+  it('should be able to override the default config', fakeAsync(() => {
+    overlayContainer.ngOnDestroy();
+    viewContainerFixture.destroy();
+
+    TestBed
+      .resetTestingModule()
+      .overrideProvider(MAT_SNACK_BAR_DEFAULT_OPTIONS, {
+        deps: [],
+        useFactory: () => ({panelClass: 'custom-class'})
+      })
+      .configureTestingModule({imports: [MatSnackBarModule, NoopAnimationsModule]})
+      .compileComponents();
+
+    inject([MatSnackBar, OverlayContainer], (sb: MatSnackBar, oc: OverlayContainer) => {
+      snackBar = sb;
+      overlayContainer = oc;
+      overlayContainerElement = oc.getContainerElement();
+    })();
+
+    snackBar.open(simpleMessage);
+    flush();
+
+    expect(overlayContainerElement.querySelector('snack-bar-container')!.classList)
+        .toContain('custom-class', 'Expected class applied through the defaults to be applied.');
+  }));
+
   describe('with custom component', () => {
     it('should open a custom component', () => {
       const snackBarRef = snackBar.openFromComponent(BurritosNotification);
@@ -504,7 +531,6 @@ describe('MatSnackBar with parent MatSnackBar', () => {
   }));
 });
 
-
 describe('MatSnackBar Positioning', () => {
   let snackBar: MatSnackBar;
   let liveAnnouncer: LiveAnnouncer;

src/lib/snack-bar/snack-bar.ts

@@ -10,7 +10,15 @@ import {LiveAnnouncer} from '@angular/cdk/a11y';
 import {BreakpointObserver, Breakpoints} from '@angular/cdk/layout';
 import {Overlay, OverlayConfig, OverlayRef} from '@angular/cdk/overlay';
 import {ComponentPortal, ComponentType, PortalInjector} from '@angular/cdk/portal';
-import {ComponentRef, Injectable, Injector, Optional, SkipSelf} from '@angular/core';
+import {
+  ComponentRef,
+  Inject,
+  Injectable,
+  Injector,
+  InjectionToken,
+  Optional,
+  SkipSelf,
+} from '@angular/core';
 import {take} from 'rxjs/operators/take';
 import {takeUntil} from 'rxjs/operators/takeUntil';
 import {SimpleSnackBar} from './simple-snack-bar';
@@ -19,6 +27,10 @@ import {MatSnackBarContainer} from './snack-bar-container';
 import {MatSnackBarRef} from './snack-bar-ref';
 
 
+/** Injection token that can be used to specify default snack bar. */
+export const MAT_SNACK_BAR_DEFAULT_OPTIONS =
+    new InjectionToken<MatSnackBarConfig>('mat-snack-bar-default-options');
+
 /**
  * Service to dispatch Material Design snack bar messages.
  */
@@ -50,7 +62,8 @@ export class MatSnackBar {
       private _live: LiveAnnouncer,
       private _injector: Injector,
       private _breakpointObserver: BreakpointObserver,
-      @Optional() @SkipSelf() private _parentSnackBar: MatSnackBar) {}
+      @Optional() @SkipSelf() private _parentSnackBar: MatSnackBar,
+      @Inject(MAT_SNACK_BAR_DEFAULT_OPTIONS) private _defaultConfig: MatSnackBarConfig) {}
 
   /**
    * Creates and dispatches a snack bar with a custom component for the content, removing any
@@ -60,7 +73,7 @@ export class MatSnackBar {
    * @param config Extra configuration for the snack bar.
    */
   openFromComponent<T>(component: ComponentType<T>, config?: MatSnackBarConfig): MatSnackBarRef<T> {
-    const _config = _applyConfigDefaults(config);
+    const _config = {...this._defaultConfig, ...config};
     const snackBarRef = this._attach(component, _config);
 
     // When the snackbar is dismissed, clear the reference to it.
@@ -104,7 +117,7 @@ export class MatSnackBar {
    */
   open(message: string, action: string = '', config?: MatSnackBarConfig):
       MatSnackBarRef<SimpleSnackBar> {
-    const _config = _applyConfigDefaults(config);
+    const _config = {...this._defaultConfig, ...config};
 
     // Since the user doesn't have access to the component, we can
     // override the data to pass in our own message and action.
@@ -216,12 +229,3 @@ export class MatSnackBar {
     return new PortalInjector(userInjector || this._injector, injectionTokens);
   }
 }
-
-/**
- * Applies default options to the snackbar config.
- * @param config The configuration to which the defaults will be applied.
- * @returns The new configuration object with defaults applied.
- */
-function _applyConfigDefaults(config?: MatSnackBarConfig): MatSnackBarConfig {
-  return {...new MatSnackBarConfig(), ...config};
-}