feat(select): add md-optgroup component

Adds the `md-optgroup` component, which can be used to group options inside of `md-select`, in a similar way to the native `optgroup`.

Fixes #3182.

src/demo-app/select/select-demo.html

@@ -1,5 +1,7 @@
-<div style="height: 1000px">This div is for testing scrolled selects.</div>
+Space above cards: <input type="number" [formControl]="topHeightCtrl">
 <button md-button (click)="showSelect=!showSelect">SHOW SELECT</button>
+<div [style.height.px]="topHeightCtrl.value"></div>
+
 <div class="demo-select">
   <md-card>
     <md-card-subtitle>ngModel</md-card-subtitle>
@@ -62,6 +64,21 @@
     </md-card-content>
   </md-card>
 
+  <md-card>
+    <md-card-subtitle>Option groups</md-card-subtitle>
+
+    <md-card-content>
+      <md-select placeholder="Pokemon" [(ngModel)]="currentPokemonFromGroup">
+        <md-optgroup *ngFor="let group of pokemonGroups" [label]="group.name"
+          [disabled]="group.disabled">
+          <md-option *ngFor="let creature of group.pokemon" [value]="creature.value">
+            {{ creature.viewValue }}
+          </md-option>
+        </md-optgroup>
+      </md-select>
+    </md-card-content>
+  </md-card>
+
   <div *ngIf="showSelect">
     <md-card>
       <md-card-subtitle>formControl</md-card-subtitle>

src/demo-app/select/select-demo.ts

@@ -16,9 +16,11 @@ export class SelectDemo {
   showSelect = false;
   currentDrink: string;
   currentPokemon: string[];
+  currentPokemonFromGroup: string;
   latestChangeEvent: MdSelectChange;
   floatPlaceholder: string = 'auto';
   foodControl = new FormControl('pizza-1');
+  topHeightCtrl = new FormControl(0);
   drinksTheme = 'primary';
   pokemonTheme = 'primary';
 
@@ -56,6 +58,41 @@ export class SelectDemo {
     {value: 'warn', name: 'Warn' }
   ];
 
+  pokemonGroups = [
+    {
+      name: 'Grass',
+      pokemon: [
+        { value: 'bulbasaur-0', viewValue: 'Bulbasaur' },
+        { value: 'oddish-1', viewValue: 'Oddish' },
+        { value: 'bellsprout-2', viewValue: 'Bellsprout' }
+      ]
+    },
+    {
+      name: 'Water',
+      pokemon: [
+        { value: 'squirtle-3', viewValue: 'Squirtle' },
+        { value: 'psyduck-4', viewValue: 'Psyduck' },
+        { value: 'horsea-5', viewValue: 'Horsea' }
+      ]
+    },
+    {
+      name: 'Fire',
+      disabled: true,
+      pokemon: [
+        { value: 'charmander-6', viewValue: 'Charmander' },
+        { value: 'vulpix-7', viewValue: 'Vulpix' },
+        { value: 'flareon-8', viewValue: 'Flareon' }
+      ]
+    },
+    {
+      name: 'Psychic',
+      pokemon: [
+        { value: 'mew-9', viewValue: 'Mew' },
+        { value: 'mewtwo-10', viewValue: 'Mewtwo' },
+      ]
+    }
+  ];
+
   toggleDisabled() {
     this.foodControl.enabled ? this.foodControl.disable() : this.foodControl.enable();
   }

src/lib/core/_core.scss

@@ -5,6 +5,8 @@
 @import 'ripple/ripple';
 @import 'option/option';
 @import 'option/option-theme';
+@import 'option/optgroup';
+@import 'option/optgroup-theme';
 @import 'selection/pseudo-checkbox/pseudo-checkbox-theme';
 
 // Mixin that renders all of the core styles that are not theme-dependent.
@@ -20,6 +22,7 @@
 
   @include mat-ripple();
   @include mat-option();
+  @include mat-optgroup();
   @include cdk-a11y();
   @include cdk-overlay();
 }
@@ -28,6 +31,7 @@
 @mixin mat-core-theme($theme) {
   @include mat-ripple-theme($theme);
   @include mat-option-theme($theme);
+  @include mat-optgroup-theme($theme);
   @include mat-pseudo-checkbox-theme($theme);
 
   // Wrapper element that provides the theme background when the

src/lib/core/core.ts

@@ -2,7 +2,7 @@ import {NgModule} from '@angular/core';
 import {MdLineModule} from './line/line';
 import {RtlModule} from './rtl/dir';
 import {ObserveContentModule} from './observe-content/observe-content';
-import {MdOptionModule} from './option/option';
+import {MdOptionModule} from './option/index';
 import {PortalModule} from './portal/portal-directives';
 import {OverlayModule} from './overlay/overlay-directives';
 import {A11yModule} from './a11y/index';
@@ -16,7 +16,7 @@ export {Dir, LayoutDirection, RtlModule} from './rtl/dir';
 // Mutation Observer
 export {ObserveContentModule, ObserveContent} from './observe-content/observe-content';
 
-export {MdOptionModule, MdOption, MdOptionSelectionChange} from './option/option';
+export * from './option/index';
 
 // Portals
 export {

src/lib/core/option/_optgroup-theme.scss

@@ -0,0 +1,14 @@
+@import '../theming/palette';
+@import '../theming/theming';
+
+@mixin mat-optgroup-theme($theme) {
+  $foreground: map-get($theme, foreground);
+
+  .mat-optgroup-label {
+    color: mat-color($foreground, secondary-text);
+  }
+
+  .mat-optgroup-disabled .mat-optgroup-label {
+    color: mat-color($foreground, hint-text);
+  }
+}

src/lib/core/option/_optgroup.scss

@@ -0,0 +1,14 @@
+@import '../style/menu-common';
+@import '../style/vendor-prefixes';
+
+@mixin mat-optgroup() {
+  .mat-optgroup-label {
+    @include mat-menu-item-base();
+    @include user-select(none);
+    cursor: default;
+
+    // TODO(crisbeto): should use the typography functions once #4375 is in.
+    font-weight: bold;
+    font-size: 14px;
+  }
+}

src/lib/core/option/_option.scss

@@ -17,6 +17,15 @@
       @include user-select(none);
       cursor: default;
     }
+
+    .mat-optgroup &:not(.mat-option-multiple) {
+      padding-left: $mat-menu-side-padding * 2;
+
+      [dir='rtl'] & {
+        padding-left: $mat-menu-side-padding;
+        padding-right: $mat-menu-side-padding * 2;
+      }
+    }
   }
 
   .mat-option-ripple {
@@ -26,7 +35,7 @@
     bottom: 0;
     right: 0;
 
-    // In high contrast mode this completely covers the text.
+    // Prevents the ripple from completely covering the option in high contrast mode.
     @include cdk-high-contrast {
       opacity: 0.5;
     }

src/lib/core/option/index.ts

@@ -0,0 +1,18 @@
+import {NgModule} from '@angular/core';
+import {CommonModule} from '@angular/common';
+import {MdRippleModule} from '../ripple/index';
+import {MdSelectionModule} from '../selection/index';
+import {MdOption} from './option';
+import {MdOptgroup} from './optgroup';
+
+
+@NgModule({
+  imports: [MdRippleModule, CommonModule, MdSelectionModule],
+  exports: [MdOption, MdOptgroup],
+  declarations: [MdOption, MdOptgroup]
+})
+export class MdOptionModule {}
+
+
+export * from './option';
+export * from './optgroup';

src/lib/core/option/optgroup.html

@@ -0,0 +1,2 @@
+<label class="mat-optgroup-label" [id]="_labelId">{{ label }}</label>
+<ng-content select="md-option, mat-option"></ng-content>

src/lib/core/option/optgroup.ts

@@ -0,0 +1,33 @@
+import {Component, ViewEncapsulation, ContentChildren, QueryList, Input} from '@angular/core';
+import {mixinDisabled, CanDisable} from '../common-behaviors/disabled';
+
+// Boilerplate for applying mixins to MdOptgroup.
+export class MdOptgroupBase { }
+export const _MdOptgroupMixinBase = mixinDisabled(MdOptgroupBase);
+
+// Counter for unique group ids.
+let nextId = 0;
+
+/**
+ * Component that is used to group instances of `md-option`.
+ */
+@Component({
+  moduleId: module.id,
+  selector: 'md-optgroup, mat-optgroup',
+  templateUrl: 'optgroup.html',
+  encapsulation: ViewEncapsulation.None,
+  inputs: ['disabled'],
+  host: {
+    'class': 'mat-optgroup',
+    '[class.mat-optgroup-disabled]': 'disabled',
+    '[attr.aria-disabled]': 'disabled.toString()',
+    '[attr.aria-labelledby]': '_labelId',
+  }
+})
+export class MdOptgroup extends _MdOptgroupMixinBase implements CanDisable {
+  /** Label for the option group. */
+  @Input() label: string;
+
+  /** Unique id for the underlying label. */
+  _labelId: string = `mat-optgroup-label-${nextId++}`;
+}

src/lib/core/option/option.ts

@@ -9,12 +9,10 @@ import {
   Inject,
   Optional,
 } from '@angular/core';
-import {CommonModule} from '@angular/common';
 import {ENTER, SPACE} from '../keyboard/keycodes';
 import {coerceBooleanProperty} from '../coercion/boolean-property';
-import {MdRippleModule} from '../ripple/index';
-import {MdSelectionModule} from '../selection/index';
 import {MATERIAL_COMPATIBILITY_MODE} from '../../core/compatibility/compatibility';
+import {MdOptgroup} from './optgroup';
 
 /**
  * Option IDs need to be unique across components, so this counter exists outside of
@@ -74,14 +72,15 @@ export class MdOption {
 
   /** Whether the option is disabled. */
   @Input()
-  get disabled() { return this._disabled; }
+  get disabled() { return (this.group && this.group.disabled) || this._disabled; }
   set disabled(value: any) { this._disabled = coerceBooleanProperty(value); }
 
   /** Event emitted when the option is selected or deselected. */
   @Output() onSelectionChange = new EventEmitter<MdOptionSelectionChange>();
 
   constructor(
     private _element: ElementRef,
+    @Optional() public readonly group: MdOptgroup,
     @Optional() @Inject(MATERIAL_COMPATIBILITY_MODE) public _isCompatibilityMode: boolean) {}
 
   /**
@@ -172,10 +171,3 @@ export class MdOption {
   }
 
 }
-
-@NgModule({
-  imports: [MdRippleModule, CommonModule, MdSelectionModule],
-  exports: [MdOption],
-  declarations: [MdOption]
-})
-export class MdOptionModule {}

src/lib/select/index.ts

@@ -1,8 +1,7 @@
 import {NgModule} from '@angular/core';
 import {CommonModule} from '@angular/common';
 import {MdSelect} from './select';
-import {MdOptionModule} from '../core/option/option';
-import {MdCommonModule, OverlayModule} from '../core';
+import {MdCommonModule, OverlayModule, MdOptionModule} from '../core';
 
 
 @NgModule({