fix: improved key manager typings (#6443)

Makes the FocusKeyManager and ActivedescendantKeyManager generic which avoids having to cast the items all the time (e.g. https://github.com/angular/material2/blob/master/src/lib/autocomplete/autocomplete-trigger.ts#L234).

Author: crisbeto

src/cdk/a11y/activedescendant-key-manager.ts

@@ -18,7 +18,7 @@ export interface Highlightable extends ListKeyManagerOption {
   setInactiveStyles(): void;
 }
 
-export class ActiveDescendantKeyManager extends ListKeyManager<Highlightable> {
+export class ActiveDescendantKeyManager<T> extends ListKeyManager<Highlightable & T> {
 
   /**
    * This method sets the active item to the item at the specified index.

src/cdk/a11y/focus-key-manager.ts

@@ -17,7 +17,7 @@ export interface FocusableOption extends ListKeyManagerOption {
   focus(): void;
 }
 
-export class FocusKeyManager extends ListKeyManager<FocusableOption> {
+export class FocusKeyManager<T> extends ListKeyManager<FocusableOption & T> {
   /**
    * This method sets the active item to the item at the specified index.
    * It also adds focuses the newly active item.

src/cdk/a11y/list-key-manager.spec.ts

@@ -451,11 +451,11 @@ describe('Key managers', () => {
   });
 
   describe('FocusKeyManager', () => {
-    let keyManager: FocusKeyManager;
+    let keyManager: FocusKeyManager<FakeFocusable>;
 
     beforeEach(() => {
       itemList.items = [new FakeFocusable(), new FakeFocusable(), new FakeFocusable()];
-      keyManager = new FocusKeyManager(itemList);
+      keyManager = new FocusKeyManager<FakeFocusable>(itemList);
 
       // first item is already focused
       keyManager.setFirstItemActive();
@@ -503,11 +503,11 @@ describe('Key managers', () => {
   });
 
   describe('ActiveDescendantKeyManager', () => {
-    let keyManager: ActiveDescendantKeyManager;
+    let keyManager: ActiveDescendantKeyManager<FakeHighlightable>;
 
     beforeEach(fakeAsync(() => {
       itemList.items = [new FakeHighlightable(), new FakeHighlightable(), new FakeHighlightable()];
-      keyManager = new ActiveDescendantKeyManager(itemList);
+      keyManager = new ActiveDescendantKeyManager<FakeHighlightable>(itemList);
 
       // first item is already focused
       keyManager.setFirstItemActive();

src/lib/autocomplete/autocomplete-trigger.ts

@@ -231,7 +231,7 @@ export class MdAutocompleteTrigger implements ControlValueAccessor, OnDestroy {
   /** The currently active option, coerced to MdOption type. */
   get activeOption(): MdOption | null {
     if (this.autocomplete && this.autocomplete._keyManager) {
-      return this.autocomplete._keyManager.activeItem as MdOption;
+      return this.autocomplete._keyManager.activeItem;
     }
 
     return null;
@@ -439,7 +439,7 @@ export class MdAutocompleteTrigger implements ControlValueAccessor, OnDestroy {
    * Clear any previous selected option and emit a selection change event for this option
    */
   private _clearPreviousSelectedOption(skip: MdOption) {
-    this.autocomplete.options.forEach((option) => {
+    this.autocomplete.options.forEach(option => {
       if (option != skip && option.selected) {
         option.deselect();
       }

src/lib/autocomplete/autocomplete.ts

@@ -43,7 +43,7 @@ let _uniqueAutocompleteIdCounter = 0;
 export class MdAutocomplete implements AfterContentInit {
 
   /** Manages active item in option list based on key events. */
-  _keyManager: ActiveDescendantKeyManager;
+  _keyManager: ActiveDescendantKeyManager<MdOption>;
 
   /** Whether the autocomplete panel should be visible, depending on option length. */
   showPanel = false;
@@ -66,7 +66,7 @@ export class MdAutocomplete implements AfterContentInit {
   constructor(private _changeDetectorRef: ChangeDetectorRef) { }
 
   ngAfterContentInit() {
-    this._keyManager = new ActiveDescendantKeyManager(this.options).withWrap();
+    this._keyManager = new ActiveDescendantKeyManager<MdOption>(this.options).withWrap();
   }
 
   /**

src/lib/chips/chip-list.spec.ts

@@ -3,13 +3,14 @@ import {Component, DebugElement, QueryList} from '@angular/core';
 import {By} from '@angular/platform-browser';
 import {NoopAnimationsModule} from '@angular/platform-browser/animations';
 import {MdChipList, MdChipsModule} from './index';
-import {FocusKeyManager} from '../core/a11y/focus-key-manager';
+import {FocusKeyManager} from '@angular/cdk/a11y';
 import {createKeyboardEvent} from '@angular/cdk/testing';
 
 import {MdInputModule} from '../input/index';
 import {LEFT_ARROW, RIGHT_ARROW, BACKSPACE, DELETE, TAB} from '../core/keyboard/keycodes';
 import {Directionality} from '../core';
 import {MdFormFieldModule} from '../form-field/index';
+import {MdChip} from './chip';
 
 describe('MdChipList', () => {
   let fixture: ComponentFixture<any>;
@@ -18,8 +19,7 @@ describe('MdChipList', () => {
   let chipListInstance: MdChipList;
   let testComponent: StandardChipList;
   let chips: QueryList<any>;
-  let manager: FocusKeyManager;
-
+  let manager: FocusKeyManager<MdChip>;
   let dir = 'ltr';
 
   beforeEach(async(() => {

src/lib/chips/chip-list.ts

@@ -21,7 +21,7 @@ import {
 } from '@angular/core';
 
 import {MdChip} from './chip';
-import {FocusKeyManager} from '../core/a11y/focus-key-manager';
+import {FocusKeyManager} from '@angular/cdk/a11y';
 import {BACKSPACE, DELETE, LEFT_ARROW, RIGHT_ARROW, UP_ARROW} from '../core/keyboard/keycodes';
 import {Directionality} from '@angular/cdk/bidi';
 import {Subscription} from 'rxjs/Subscription';
@@ -77,7 +77,7 @@ export class MdChipList implements AfterContentInit, OnDestroy {
   _tabIndex = 0;
 
   /** The FocusKeyManager which handles focus. */
-  _keyManager: FocusKeyManager;
+  _keyManager: FocusKeyManager<MdChip>;
 
   /** The chip components contained within this chip list. */
   chips: QueryList<MdChip>;
@@ -87,7 +87,7 @@ export class MdChipList implements AfterContentInit, OnDestroy {
   }
 
   ngAfterContentInit(): void {
-    this._keyManager = new FocusKeyManager(this.chips).withWrap();
+    this._keyManager = new FocusKeyManager<MdChip>(this.chips).withWrap();
 
     // Prevents the chip list from capturing focus and redirecting
     // it back to the first chip when the user tabs out.

src/lib/core/a11y/activedescendant-key-manager.ts

@@ -18,7 +18,7 @@ export interface Highlightable extends ListKeyManagerOption {
   setInactiveStyles(): void;
 }
 
-export class ActiveDescendantKeyManager extends ListKeyManager<Highlightable> {
+export class ActiveDescendantKeyManager<T> extends ListKeyManager<Highlightable & T> {
 
   /**
    * This method sets the active item to the item at the specified index.

src/lib/core/a11y/focus-key-manager.ts

@@ -17,7 +17,7 @@ export interface FocusableOption extends ListKeyManagerOption {
   focus(): void;
 }
 
-export class FocusKeyManager extends ListKeyManager<FocusableOption> {
+export class FocusKeyManager<T> extends ListKeyManager<FocusableOption & T> {
   /**
    * This method sets the active item to the item at the specified index.
    * It also adds focuses the newly active item.

src/lib/list/selection-list.ts

@@ -202,10 +202,10 @@ export class MdSelectionList extends _MdSelectionListMixinBase
   private _optionDestroyStream: Subscription;
 
   /** The FocusKeyManager which handles focus. */
-  _keyManager: FocusKeyManager;
+  _keyManager: FocusKeyManager<MdListOption>;
 
   /** The option components contained within this selection-list. */
-  @ContentChildren(MdListOption) options;
+  @ContentChildren(MdListOption) options: QueryList<MdListOption>;
 
   /** options which are selected. */
   selectedOptions: SelectionModel<MdListOption> = new SelectionModel<MdListOption>(true);
@@ -223,7 +223,7 @@ export class MdSelectionList extends _MdSelectionListMixinBase
   }
 
   ngAfterContentInit(): void {
-    this._keyManager = new FocusKeyManager(this.options).withWrap();
+    this._keyManager = new FocusKeyManager<MdListOption>(this.options).withWrap();
 
     if (this.disabled) {
       this._tabIndex = -1;