feat(material-experimental/mdc-tabs): add default fitInkBarToContent option

src/material-experimental/mdc-tabs/tab-group.spec.ts

@@ -6,7 +6,7 @@ import {By} from '@angular/platform-browser';
 import {BrowserAnimationsModule, NoopAnimationsModule} from '@angular/platform-browser/animations';
 import {CommonModule} from '@angular/common';
 import {Observable} from 'rxjs';
-import {MatTab, MatTabGroup, MatTabHeaderPosition, MatTabsModule} from './index';
+import {MAT_TABS_CONFIG, MatTab, MatTabGroup, MatTabHeaderPosition, MatTabsModule} from './index';
 
 
 describe('MatTabGroup', () => {
@@ -698,6 +698,7 @@ describe('MatTabGroup with ink bar fit to content', () => {
     const tabElement = fixture.nativeElement.querySelector('.mdc-tab');
     const contentElement = tabElement.querySelector('.mdc-tab__content');
     const indicatorElement = tabElement.querySelector('.mdc-tab-indicator');
+    expect(indicatorElement.parentElement).toBeTruthy();
     expect(indicatorElement.parentElement).toBe(contentElement);
   });
 
@@ -707,12 +708,44 @@ describe('MatTabGroup with ink bar fit to content', () => {
 
     const tabElement = fixture.nativeElement.querySelector('.mdc-tab');
     const indicatorElement = tabElement.querySelector('.mdc-tab-indicator');
+    expect(indicatorElement.parentElement).toBeTruthy();
     expect(indicatorElement.parentElement).toBe(tabElement);
 
     fixture.componentInstance.fitInkBarToContent = true;
     fixture.detectChanges();
 
     const contentElement = tabElement.querySelector('.mdc-tab__content');
+    expect(indicatorElement.parentElement).toBeTruthy();
+    expect(indicatorElement.parentElement).toBe(contentElement);
+  });
+});
+
+
+describe('MatTabNavBar with a default config', () => {
+  let fixture: ComponentFixture<SimpleTabsTestApp>;
+
+  beforeEach(fakeAsync(() => {
+    TestBed.configureTestingModule({
+      imports: [MatTabsModule, BrowserAnimationsModule],
+      declarations: [SimpleTabsTestApp],
+      providers: [
+        {provide: MAT_TABS_CONFIG, useValue: {fitInkBarToContent: true}}
+      ]
+    });
+
+    TestBed.compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(SimpleTabsTestApp);
+    fixture.detectChanges();
+  });
+
+  it('should set whether the ink bar fits to content', () => {
+    const tabElement = fixture.nativeElement.querySelector('.mdc-tab');
+    const contentElement = tabElement.querySelector('.mdc-tab__content');
+    const indicatorElement = tabElement.querySelector('.mdc-tab-indicator');
+    expect(indicatorElement.parentElement).toBeTruthy();
     expect(indicatorElement.parentElement).toBe(contentElement);
   });
 });

src/material-experimental/mdc-tabs/tab-group.ts

@@ -70,5 +70,7 @@ export class MatTabGroup extends _MatTabGroupBase {
               @Inject(MAT_TABS_CONFIG) @Optional() defaultConfig?: MatTabsConfig,
               @Optional() @Inject(ANIMATION_MODULE_TYPE) animationMode?: string) {
     super(elementRef, changeDetectorRef, defaultConfig, animationMode);
+    this.fitInkBarToContent = defaultConfig && defaultConfig.fitInkBarToContent != null ?
+        defaultConfig.fitInkBarToContent : false;
   }
 }

src/material-experimental/mdc-tabs/tab-nav-bar/tab-nav-bar.spec.ts

@@ -7,6 +7,8 @@ import {Direction, Directionality} from '@angular/cdk/bidi';
 import {Subject} from 'rxjs';
 import {MatTabsModule} from '../module';
 import {MatTabLink, MatTabNav} from './tab-nav-bar';
+import {BrowserAnimationsModule} from '@angular/platform-browser/animations';
+import {MAT_TABS_CONFIG} from '../index';
 
 
 describe('MatTabNavBar', () => {
@@ -335,6 +337,7 @@ describe('MatTabNavBar', () => {
       const tabElement = fixture.nativeElement.querySelector('.mdc-tab');
       const contentElement = tabElement.querySelector('.mdc-tab__content');
       const indicatorElement = tabElement.querySelector('.mdc-tab-indicator');
+      expect(indicatorElement.parentElement).toBeTruthy();
       expect(indicatorElement.parentElement).toBe(contentElement);
     });
 
@@ -344,17 +347,49 @@ describe('MatTabNavBar', () => {
 
       const tabElement = fixture.nativeElement.querySelector('.mdc-tab');
       const indicatorElement = tabElement.querySelector('.mdc-tab-indicator');
+      expect(indicatorElement.parentElement).toBeTruthy();
       expect(indicatorElement.parentElement).toBe(tabElement);
 
       fixture.componentInstance.fitInkBarToContent = true;
       fixture.detectChanges();
 
       const contentElement = tabElement.querySelector('.mdc-tab__content');
+      expect(indicatorElement.parentElement).toBeTruthy();
       expect(indicatorElement.parentElement).toBe(contentElement);
     });
   });
 });
 
+describe('MatTabNavBar with a default config', () => {
+  let fixture: ComponentFixture<TabLinkWithTabIndexBinding>;
+
+  beforeEach(fakeAsync(() => {
+    TestBed.configureTestingModule({
+      imports: [MatTabsModule, BrowserAnimationsModule],
+      declarations: [TabLinkWithTabIndexBinding],
+      providers: [
+        {provide: MAT_TABS_CONFIG, useValue: {fitInkBarToContent: true}}
+      ]
+    });
+
+    TestBed.compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(TabLinkWithTabIndexBinding);
+    fixture.detectChanges();
+  });
+
+  it('should set whether the ink bar fits to content', () => {
+    const tabElement = fixture.nativeElement.querySelector('.mdc-tab');
+    const contentElement = tabElement.querySelector('.mdc-tab__content');
+    const indicatorElement = tabElement.querySelector('.mdc-tab-indicator');
+    expect(indicatorElement.parentElement).toBeTruthy();
+    expect(indicatorElement.parentElement).toBe(contentElement);
+  });
+});
+
+
 @Component({
   selector: 'test-app',
   template: `

src/material-experimental/mdc-tabs/tab-nav-bar/tab-nav-bar.ts

@@ -25,7 +25,12 @@ import {
 import {ANIMATION_MODULE_TYPE} from '@angular/platform-browser/animations';
 import {MAT_RIPPLE_GLOBAL_OPTIONS, RippleGlobalOptions} from '@angular/material/core';
 import {FocusMonitor} from '@angular/cdk/a11y';
-import {_MatTabNavBase, _MatTabLinkBase} from '@angular/material/tabs';
+import {
+  _MatTabNavBase,
+  _MatTabLinkBase,
+  MAT_TABS_CONFIG,
+  MatTabsConfig
+} from '@angular/material/tabs';
 import {DOCUMENT} from '@angular/common';
 import {Directionality} from '@angular/cdk/bidi';
 import {ViewportRuler} from '@angular/cdk/scrolling';
@@ -81,8 +86,13 @@ export class MatTabNav extends _MatTabNavBase implements AfterContentInit {
                * @deprecated @breaking-change 9.0.0 `platform` parameter to become required.
                */
               @Optional() platform?: Platform,
-              @Optional() @Inject(ANIMATION_MODULE_TYPE) animationMode?: string) {
+              @Optional() @Inject(ANIMATION_MODULE_TYPE) animationMode?: string,
+              @Optional() @Inject(MAT_TABS_CONFIG) defaultConfig?: MatTabsConfig) {
     super(elementRef, dir, ngZone, changeDetectorRef, viewportRuler, platform, animationMode);
+    this.disablePagination = defaultConfig && defaultConfig.disablePagination != null ?
+        defaultConfig.disablePagination : false;
+    this.fitInkBarToContent = defaultConfig && defaultConfig.fitInkBarToContent != null ?
+        defaultConfig.fitInkBarToContent : false;
   }
 
   ngAfterContentInit() {

src/material/tabs/public-api.ts

@@ -24,3 +24,4 @@ export {MatTabNav, MatTabLink, _MatTabNavBase, _MatTabLinkBase} from './tab-nav-
 export {MatTabContent} from './tab-content';
 export {ScrollDirection} from './paginated-tab-header';
 export * from './tabs-animations';
+export {MAT_TABS_CONFIG, MatTabsConfig} from './tab-config';

src/material/tabs/tab-config.ts

@@ -0,0 +1,29 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {InjectionToken} from '@angular/core';
+
+/** Object that can be used to configure the default options for the tabs module. */
+export interface MatTabsConfig {
+  /** Duration for the tab animation. Must be a valid CSS value (e.g. 600ms). */
+  animationDuration?: string;
+
+  /**
+   * Whether pagination should be disabled. This can be used to avoid unnecessary
+   * layout recalculations if it's known that pagination won't be required.
+   */
+  disablePagination?: boolean;
+
+  /**
+   * Whether the ink bar should fit its width to the size of the tab label content.
+   * This only applies to the MDC-based tabs.
+   */
+  fitInkBarToContent?: boolean;
+}
+
+/** Injection token that can be used to provide the default options the tabs module. */
+export const MAT_TABS_CONFIG = new InjectionToken<MatTabsConfig>('MAT_TABS_CONFIG');

src/material/tabs/tab-group.ts

@@ -14,18 +14,17 @@ import {
   ChangeDetectorRef,
   Component,
   ContentChildren,
+  Directive,
   ElementRef,
   EventEmitter,
+  Inject,
   Input,
   OnDestroy,
+  Optional,
   Output,
   QueryList,
   ViewChild,
   ViewEncapsulation,
-  Optional,
-  Inject,
-  InjectionToken,
-  Directive,
 } from '@angular/core';
 import {
   CanColor,
@@ -39,7 +38,8 @@ import {
 import {ANIMATION_MODULE_TYPE} from '@angular/platform-browser/animations';
 import {merge, Subscription} from 'rxjs';
 import {startWith} from 'rxjs/operators';
-import {MatTab, MAT_TAB_GROUP} from './tab';
+import {MAT_TAB_GROUP, MatTab} from './tab';
+import {MAT_TABS_CONFIG, MatTabsConfig} from './tab-config';
 
 
 /** Used to generate unique ID's for each tab component */
@@ -56,21 +56,6 @@ export class MatTabChangeEvent {
 /** Possible positions for the tab header. */
 export type MatTabHeaderPosition = 'above' | 'below';
 
-/** Object that can be used to configure the default options for the tabs module. */
-export interface MatTabsConfig {
-  /** Duration for the tab animation. Must be a valid CSS value (e.g. 600ms). */
-  animationDuration?: string;
-
-  /**
-   * Whether pagination should be disabled. This can be used to avoid unnecessary
-   * layout recalculations if it's known that pagination won't be required.
-   */
-  disablePagination?: boolean;
-}
-
-/** Injection token that can be used to provide the default options the tabs module. */
-export const MAT_TABS_CONFIG = new InjectionToken<MatTabsConfig>('MAT_TABS_CONFIG');
-
 // Boilerplate for applying mixins to MatTabGroup.
 /** @docs-private */
 class MatTabGroupMixinBase {

tools/public_api_guard/material/tabs.d.ts

@@ -199,6 +199,7 @@ export declare const matTabsAnimations: {
 export interface MatTabsConfig {
     animationDuration?: string;
     disablePagination?: boolean;
+    fitInkBarToContent?: boolean;
 }
 
 export declare class MatTabsModule {