fix(slide-toggle): support native tabindex attribute (#6613)

Currently the slide-toggle only allows changing the tabIndex using the `tabIndex` binding. Using the native `tabindex` attribute doesn't have any affect. With this change the native tabindex property will be respected.

References #6465

src/lib/core/common-behaviors/tabindex.spec.ts

@@ -0,0 +1,48 @@
+import {mixinTabIndex} from './tabindex';
+
+describe('mixinTabIndex', () => {
+
+  it('should augment an existing class with a tabIndex property', () => {
+    const classWithMixin = mixinTabIndex(TestClass);
+    const instance = new classWithMixin();
+
+    expect(instance.tabIndex)
+      .toBe(0, 'Expected the mixed-into class to have a tabIndex property');
+
+    instance.tabIndex = 4;
+
+    expect(instance.tabIndex)
+      .toBe(4, 'Expected the mixed-into class to have an updated tabIndex property');
+  });
+
+  it('should set tabIndex to `-1` if the disabled property is set to true', () => {
+    const classWithMixin = mixinTabIndex(TestClass);
+    const instance = new classWithMixin();
+
+    expect(instance.tabIndex)
+      .toBe(0, 'Expected tabIndex to be set to 0 initially');
+
+    instance.disabled = true;
+
+    expect(instance.tabIndex)
+      .toBe(-1, 'Expected tabIndex to be set to -1 if the disabled property is set to true');
+  });
+
+  it('should allow having a custom default tabIndex value', () => {
+    const classWithMixin = mixinTabIndex(TestClass, 20);
+    const instance = new classWithMixin();
+
+    expect(instance.tabIndex)
+      .toBe(20, 'Expected tabIndex to be set to 20 initially');
+
+    instance.tabIndex = 0;
+
+    expect(instance.tabIndex)
+      .toBe(0, 'Expected tabIndex to still support 0 as value');
+  });
+
+});
+
+class TestClass {
+  disabled = false;
+}

src/lib/core/common-behaviors/tabindex.ts

@@ -0,0 +1,34 @@
+/**
+ * @license
+ * Copyright Google Inc. 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 {Constructor} from './constructor';
+import {CanDisable} from './disabled';
+
+/** @docs-private */
+export interface HasTabIndex {
+  tabIndex: number;
+}
+
+/** Mixin to augment a directive with a `tabIndex` property. */
+export function mixinTabIndex<T extends Constructor<CanDisable>>(base: T, defaultTabIndex = 0)
+    : Constructor<HasTabIndex> & T {
+  return class extends base {
+    private _tabIndex: number = defaultTabIndex;
+
+    get tabIndex(): number { return this.disabled ? -1 : this._tabIndex; }
+    set tabIndex(value: number) {
+      // If the specified tabIndex value is null or undefined, fall back to the default value.
+      this._tabIndex = value != null ? value : defaultTabIndex;
+    }
+
+    constructor(...args: any[]) {
+      super(...args);
+    }
+  };
+}
+

src/lib/select/select.ts

@@ -66,6 +66,7 @@ import {
   PlaceholderOptions
 } from '../core/placeholder/placeholder-options';
 import {Platform} from '@angular/cdk/platform';
+import {HasTabIndex, mixinTabIndex} from '../core/common-behaviors/tabindex';
 
 /**
  * The following style constants are necessary to save here in order
@@ -155,7 +156,8 @@ export class MdSelectChange {
 export class MdSelectBase {
   constructor(public _renderer: Renderer2, public _elementRef: ElementRef) {}
 }
-export const _MdSelectMixinBase = mixinColor(mixinDisabled(MdSelectBase), 'primary');
+export const _MdSelectMixinBase =
+  mixinTabIndex(mixinColor(mixinDisabled(MdSelectBase), 'primary'));
 
 
 /**
@@ -172,7 +174,7 @@ export class MdSelectTrigger {}
   selector: 'md-select, mat-select',
   templateUrl: 'select.html',
   styleUrls: ['select.css'],
-  inputs: ['color', 'disabled'],
+  inputs: ['color', 'disabled', 'tabIndex'],
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush,
   host: {
@@ -200,7 +202,7 @@ export class MdSelectTrigger {}
   exportAs: 'mdSelect',
 })
 export class MdSelect extends _MdSelectMixinBase implements AfterContentInit, OnDestroy, OnInit,
-    ControlValueAccessor, CanColor, CanDisable {
+    ControlValueAccessor, CanColor, CanDisable, HasTabIndex {
   /** Whether or not the overlay panel is open. */
   private _panelOpen = false;
 
@@ -234,9 +236,6 @@ export class MdSelect extends _MdSelectMixinBase implements AfterContentInit, On
   /** The animation state of the placeholder. */
   private _placeholderState = '';
 
-  /** Tab index for the element. */
-  private _tabIndex: number;
-
   /** Deals with configuring placeholder options */
   private _placeholderOptions: PlaceholderOptions;
 
@@ -371,15 +370,6 @@ export class MdSelect extends _MdSelectMixinBase implements AfterContentInit, On
   }
   private _floatPlaceholder: FloatPlaceholderType;
 
-  /** Tab index for the select element. */
-  @Input()
-  get tabIndex(): number { return this.disabled ? -1 : this._tabIndex; }
-  set tabIndex(value: number) {
-    if (typeof value !== 'undefined') {
-      this._tabIndex = value;
-    }
-  }
-
   /** Value of the select control. */
   @Input()
   get value() { return this._value; }
@@ -445,7 +435,7 @@ export class MdSelect extends _MdSelectMixinBase implements AfterContentInit, On
       this._control.valueAccessor = this;
     }
 
-    this._tabIndex = parseInt(tabIndex) || 0;
+    this.tabIndex = parseInt(tabIndex) || 0;
     this._placeholderOptions = placeholderOptions ? placeholderOptions : {};
     this.floatPlaceholder = this._placeholderOptions.float || 'auto';
   }

src/lib/slide-toggle/slide-toggle.spec.ts

@@ -16,7 +16,7 @@ describe('MdSlideToggle without forms', () => {
   beforeEach(async(() => {
     TestBed.configureTestingModule({
       imports: [MdSlideToggleModule],
-      declarations: [SlideToggleBasic],
+      declarations: [SlideToggleBasic, SlideToggleWithTabindexAttr],
       providers: [
         {provide: HAMMER_GESTURE_CONFIG, useFactory: () => gestureConfig = new TestGestureConfig()}
       ]
@@ -333,6 +333,18 @@ describe('MdSlideToggle without forms', () => {
 
       expect(fixture.componentInstance.lastEvent).toBeFalsy();
     }));
+
+    it('should be able to set the tabindex via the native attribute', async(() => {
+      const fixture = TestBed.createComponent(SlideToggleWithTabindexAttr);
+
+      fixture.detectChanges();
+
+      const slideToggle = fixture.debugElement
+        .query(By.directive(MdSlideToggle)).componentInstance as MdSlideToggle;
+
+      expect(slideToggle.tabIndex)
+        .toBe(5, 'Expected tabIndex property to have been set based on the native attribute');
+    }));
   });
 
   describe('with dragging', () => {
@@ -789,3 +801,8 @@ class SlideToggleWithModel {
 class SlideToggleWithFormControl {
   formControl = new FormControl();
 }
+
+@Component({
+  template: `<md-slide-toggle tabindex="5"></md-slide-toggle>`
+})
+class SlideToggleWithTabindexAttr {}

src/lib/slide-toggle/slide-toggle.ts

@@ -8,6 +8,7 @@
 
 import {
   AfterContentInit,
+  Attribute,
   ChangeDetectionStrategy,
   ChangeDetectorRef,
   Component,
@@ -35,6 +36,7 @@ import {ControlValueAccessor, NG_VALUE_ACCESSOR} from '@angular/forms';
 import {mixinDisabled, CanDisable} from '../core/common-behaviors/disabled';
 import {CanColor, mixinColor} from '../core/common-behaviors/color';
 import {CanDisableRipple, mixinDisableRipple} from '../core/common-behaviors/disable-ripple';
+import {HasTabIndex, mixinTabIndex} from '../core/common-behaviors/tabindex';
 
 // Increasing integer for generating unique ids for slide-toggle components.
 let nextUniqueId = 0;
@@ -57,7 +59,7 @@ export class MdSlideToggleBase {
   constructor(public _renderer: Renderer2, public _elementRef: ElementRef) {}
 }
 export const _MdSlideToggleMixinBase =
-  mixinColor(mixinDisableRipple(mixinDisabled(MdSlideToggleBase)), 'accent');
+  mixinTabIndex(mixinColor(mixinDisableRipple(mixinDisabled(MdSlideToggleBase)), 'accent'));
 
 /** Represents a slidable "switch" toggle that can be moved between on and off. */
 @Component({
@@ -73,12 +75,12 @@ export const _MdSlideToggleMixinBase =
   templateUrl: 'slide-toggle.html',
   styleUrls: ['slide-toggle.css'],
   providers: [MD_SLIDE_TOGGLE_VALUE_ACCESSOR],
-  inputs: ['disabled', 'disableRipple', 'color'],
+  inputs: ['disabled', 'disableRipple', 'color', 'tabIndex'],
   encapsulation: ViewEncapsulation.None,
   changeDetection: ChangeDetectionStrategy.OnPush
 })
 export class MdSlideToggle extends _MdSlideToggleMixinBase implements OnDestroy, AfterContentInit,
-    ControlValueAccessor, CanDisable, CanColor, CanDisableRipple {
+    ControlValueAccessor, CanDisable, CanColor, HasTabIndex, CanDisableRipple {
 
   private onChange = (_: any) => {};
   private onTouched = () => {};
@@ -97,9 +99,6 @@ export class MdSlideToggle extends _MdSlideToggleMixinBase implements OnDestroy,
   /** A unique id for the slide-toggle input. If none is supplied, it will be auto-generated. */
   @Input() id: string = this._uniqueId;
 
-  /** Used to specify the tabIndex value for the underlying input element. */
-  @Input() tabIndex: number = 0;
-
   /** Whether the label should appear after or before the slide-toggle. Defaults to 'after' */
   @Input() labelPosition: 'before' | 'after' = 'after';
 
@@ -139,8 +138,11 @@ export class MdSlideToggle extends _MdSlideToggleMixinBase implements OnDestroy,
               renderer: Renderer2,
               private _platform: Platform,
               private _focusOriginMonitor: FocusOriginMonitor,
-              private _changeDetectorRef: ChangeDetectorRef) {
+              private _changeDetectorRef: ChangeDetectorRef,
+              @Attribute('tabindex') tabIndex: string) {
     super(renderer, elementRef);
+
+    this.tabIndex = parseInt(tabIndex) || 0;
   }
 
   ngAfterContentInit() {