Add two way binding to slider

src/components/slider/slider.spec.ts

@@ -6,6 +6,7 @@ import {
     ComponentFixture,
     TestBed,
 } from '@angular/core/testing';
+import {ReactiveFormsModule, FormControl} from '@angular/forms';
 import {Component, DebugElement, ViewEncapsulation} from '@angular/core';
 import {By} from '@angular/platform-browser';
 import {MdSlider, MdSliderModule} from './slider';
@@ -18,7 +19,7 @@ describe('MdSlider', () => {
 
   beforeEach(async(() => {
     TestBed.configureTestingModule({
-      imports: [MdSliderModule],
+      imports: [MdSliderModule, ReactiveFormsModule],
       declarations: [
         StandardSlider,
         DisabledSlider,
@@ -28,6 +29,7 @@ describe('MdSlider', () => {
         SliderWithAutoTickInterval,
         SliderWithSetTickInterval,
         SliderWithThumbLabel,
+        SliderWithTwoWayBinding,
       ],
     });
 
@@ -588,6 +590,67 @@ describe('MdSlider', () => {
       expect(sliderContainerElement.classList).toContain('md-slider-active');
     });
   });
+
+  describe('slider as a custom form control', () => {
+    let fixture: ComponentFixture<SliderWithTwoWayBinding>;
+    let sliderDebugElement: DebugElement;
+    let sliderNativeElement: HTMLElement;
+    let sliderInstance: MdSlider;
+    let sliderTrackElement: HTMLElement;
+    let testComponent: SliderWithTwoWayBinding;
+
+    beforeEach(async(() => {
+      builder.createAsync(SliderWithTwoWayBinding).then(f => {
+        fixture = f;
+        fixture.detectChanges();
+
+        testComponent = fixture.debugElement.componentInstance;
+
+        sliderDebugElement = fixture.debugElement.query(By.directive(MdSlider));
+        sliderNativeElement = sliderDebugElement.nativeElement;
+        sliderInstance = sliderDebugElement.injector.get(MdSlider);
+        sliderTrackElement = <HTMLElement>sliderNativeElement.querySelector('.md-slider-track');
+      });
+    }));
+
+    it('should update the control when the value is updated', () => {
+      expect(testComponent.control.value).toBe(0);
+
+      sliderInstance.value = 11;
+      fixture.detectChanges();
+
+      expect(testComponent.control.value).toBe(11);
+    });
+
+    it('should update the control on click', () => {
+      expect(testComponent.control.value).toBe(0);
+
+      dispatchClickEvent(sliderTrackElement, 0.76);
+      fixture.detectChanges();
+
+      expect(testComponent.control.value).toBe(76);
+    });
+
+    it('should update the control on slide', () => {
+      expect(testComponent.control.value).toBe(0);
+
+      dispatchSlideEvent(sliderTrackElement, sliderNativeElement, 0, 0.19, gestureConfig);
+      fixture.detectChanges();
+
+      expect(testComponent.control.value).toBe(19);
+    });
+
+    it('should update the value when the control is set', () => {
+      expect(sliderInstance.value).toBe(0);
+
+      testComponent.control.setValue(7);
+      fixture.detectChanges();
+
+      expect(sliderInstance.value).toBe(7);
+    });
+
+    // TODO: Add tests for ng-pristine, ng-touched, ng-invalid.
+  });
 });
 
 // The transition has to be removed in order to test the updated positions without setTimeout.
@@ -655,6 +718,13 @@ class SliderWithSetTickInterval { }
 })
 class SliderWithThumbLabel { }
 
+@Component({
+  template: `<md-slider [formControl]="control"></md-slider>`
+})
+class SliderWithTwoWayBinding {
+  control = new FormControl('');
+}
+
 /**
  * Dispatches a click event from an element.
  * Note: The mouse event truncates the position for the click.

src/components/slider/slider.ts

@@ -6,7 +6,13 @@ import {
   Input,
   ViewEncapsulation,
   AfterContentInit,
+  forwardRef,
 } from '@angular/core';
+import {
+  NG_VALUE_ACCESSOR,
+  ControlValueAccessor,
+  FormsModule,
+} from '@angular/forms';
 import {HAMMER_GESTURE_CONFIG} from '@angular/platform-browser';
 import {BooleanFieldValue} from '@angular2-material/core/annotations/field-value';
 import {applyCssTransform} from '@angular2-material/core/style/apply-transform';
@@ -18,9 +24,20 @@ import {MdGestureConfig} from '@angular2-material/core/core';
  */
 const MIN_AUTO_TICK_SEPARATION = 30;
 
+/**
+ * Provider Expression that allows md-slider to register as a ControlValueAccessor.
+ * This allows it to support [(ngModel)] and [formControl].
+ */
+export const MD_SLIDER_VALUE_ACCESSOR: any = {
+  provide: NG_VALUE_ACCESSOR,
+  useExisting: forwardRef(() => MdSlider),
+  multi: true
+};
+
 @Component({
   moduleId: module.id,
   selector: 'md-slider',
+  providers: [MD_SLIDER_VALUE_ACCESSOR],
   host: {
     'tabindex': '0',
     '(click)': 'onClick($event)',
@@ -34,7 +51,7 @@ const MIN_AUTO_TICK_SEPARATION = 30;
   styleUrls: ['slider.css'],
   encapsulation: ViewEncapsulation.None,
 })
-export class MdSlider implements AfterContentInit {
+export class MdSlider implements AfterContentInit, ControlValueAccessor {
   /** A renderer to handle updating the slider's thumb and fill track. */
   private _renderer: SliderRenderer = null;
 
@@ -61,6 +78,11 @@ export class MdSlider implements AfterContentInit {
   /** The percentage of the slider that coincides with the value. */
   private _percent: number = 0;
 
+  private _controlValueAccessorChangeFn: (value: any) => void = (value) => {};
+
+  /** onTouch function registered via registerOnTouch (ControlValueAccessor). */
+  onTouched: () => any = () => {};
+
   /** The values at which the thumb will snap. */
   @Input() step: number = 1;
 
@@ -123,8 +145,15 @@ export class MdSlider implements AfterContentInit {
   }
 
   set value(v: number) {
+    // Only set the value to a valid number. v is casted to an any as we know it will come in as a
+    // string but it is labeled as a number which causes parseFloat to not accept it.
+    if (isNaN(parseFloat(<any> v))) {
+      return;
+    }
+
     this._value = Number(v);
     this._isInitialized = true;
+    this._controlValueAccessorChangeFn(this._value);
   }
 
   constructor(elementRef: ElementRef) {
@@ -138,7 +167,10 @@ export class MdSlider implements AfterContentInit {
    */
   ngAfterContentInit() {
     this._sliderDimensions = this._renderer.getSliderDimensions();
-    this.snapToValue();
+    // This needs to be called after content init because the value can be set to the min if the
+    // value itself isn't set. If this happens, the control value accessor needs to be updated.
+    this._controlValueAccessorChangeFn(this.value);
+    this.snapThumbToValue();
     this._updateTickSeparation();
   }
 
@@ -152,7 +184,7 @@ export class MdSlider implements AfterContentInit {
     this.isSliding = false;
     this._renderer.addFocus();
     this.updateValueFromPosition(event.clientX);
-    this.snapToValue();
+    this.snapThumbToValue();
   }
 
   /** TODO: internal */
@@ -182,7 +214,7 @@ export class MdSlider implements AfterContentInit {
   /** TODO: internal */
   onSlideEnd() {
     this.isSliding = false;
-      this.snapToValue();
+    this.snapThumbToValue();
   }
 
   /** TODO: internal */
@@ -196,6 +228,7 @@ export class MdSlider implements AfterContentInit {
   /** TODO: internal */
   onBlur() {
     this.isActive = false;
+    this.onTouched();
   }
 
   /**
@@ -230,7 +263,7 @@ export class MdSlider implements AfterContentInit {
    * Snaps the thumb to the current value.
    * Called after a click or drag event is over.
    */
-  snapToValue() {
+  snapThumbToValue() {
     this.updatePercentFromValue();
     this._renderer.updateThumbAndFillPosition(this._percent, this._sliderDimensions.width);
   }
@@ -315,6 +348,34 @@ export class MdSlider implements AfterContentInit {
   clamp(value: number, min = 0, max = 1) {
     return Math.max(min, Math.min(value, max));
   }
+
+  /**
+   * Implemented as part of ControlValueAccessor.
+   * TODO: internal
+   */
+  writeValue(value: any) {
+    this.value = value;
+
+    if (this._sliderDimensions) {
+      this.snapThumbToValue();
+    }
+  }
+
+  /**
+   * Implemented as part of ControlValueAccessor.
+   * TODO: internal
+   */
+  registerOnChange(fn: (value: any) => void) {
+    this._controlValueAccessorChangeFn = fn;
+  }
+
+  /**
+   * Implemented as part of ControlValueAccessor.
+   * TODO: internal
+   */
+  registerOnTouched(fn: any) {
+    this.onTouched = fn;
+  }
 }
 
 /**
@@ -392,6 +453,7 @@ export const MD_SLIDER_DIRECTIVES = [MdSlider];
 
 
 @NgModule({
+  imports: [FormsModule],
   exports: MD_SLIDER_DIRECTIVES,
   declarations: MD_SLIDER_DIRECTIVES,
   providers: [

src/demo-app/slider/slider-demo.html

@@ -1,35 +1,29 @@
 <h1>Default Slider</h1>
-<section class="demo-section">
-  Label <md-slider #slidey></md-slider>
-  {{slidey.value}}
-</section>
+Label <md-slider #slidey></md-slider>
+{{slidey.value}}
 
 <h1>Slider with Min and Max</h1>
-<section class="demo-section">
-  <md-slider min="5" max="7" #slider2></md-slider>
-  {{slider2.value}}
-</section>
+<md-slider min="5" max="7" #slider2></md-slider>
+{{slider2.value}}
 
 <h1>Disabled Slider</h1>
-<section class="demo-section">
-  <md-slider disabled #slider3></md-slider>
-  {{slider3.value}}
-</section>
+<md-slider disabled #slider3></md-slider>
+{{slider3.value}}
 
 <h1>Slider with set value</h1>
-<section class="demo-section">
-  <md-slider value="43" #slider4></md-slider>
-</section>
+<md-slider value="43"></md-slider>
 
 <h1>Slider with step defined</h1>
-<section class="demo-section">
-  <md-slider min="1" max="100" step="20" #slider5></md-slider>
-  {{slider5.value}}
-</section>
+<md-slider min="1" max="100" step="20" #slider5></md-slider>
+{{slider5.value}}
 
 <h1>Slider with set tick interval</h1>
 <md-slider tick-interval="auto"></md-slider>
 <md-slider tick-interval="9"></md-slider>
 
 <h1>Slider with Thumb Label</h1>
 <md-slider thumb-label></md-slider>
+
+<h1>Slider with two-way binding</h1>
+<md-slider [(ngModel)]="demo" step="40"></md-slider>
+<input [(ngModel)]="demo">