feat(cdk-experimental/listbox): selection logic and testing for listb…

…ox. (#19690)

src/cdk-experimental/listbox/BUILD.bazel

@@ -1,4 +1,4 @@
-load("//tools:defaults.bzl", "ng_module")
+load("//tools:defaults.bzl", "ng_module", "ng_test_library", "ng_web_test_suite")
 
 package(default_visibility = ["//visibility:public"])
 
@@ -9,4 +9,25 @@ ng_module(
         exclude = ["**/*.spec.ts"],
     ),
     module_name = "@angular/cdk-experimental/listbox",
+    deps = [
+        "//src/cdk/coercion",
+    ],
+)
+
+ng_test_library(
+    name = "unit_test_sources",
+    srcs = glob(
+        ["**/*.spec.ts"],
+        exclude = ["**/*.e2e.spec.ts"],
+    ),
+    deps = [
+        ":listbox",
+        "//src/cdk/testing/private",
+        "@npm//@angular/platform-browser",
+    ],
+)
+
+ng_web_test_suite(
+    name = "unit_tests",
+    deps = [":unit_test_sources"],
 )

src/cdk-experimental/listbox/listbox.spec.ts

@@ -0,0 +1,99 @@
+import {
+  ComponentFixture,
+  async,
+  TestBed,
+} from '@angular/core/testing';
+import {Component, DebugElement} from '@angular/core';
+import {By} from '@angular/platform-browser';
+import {
+  CdkOption,
+  CdkListboxModule, ListboxSelectionChangeEvent
+} from './index';
+import {dispatchMouseEvent} from '@angular/cdk/testing/private';
+
+describe('CdkOption', () => {
+
+  describe('selection state change', () => {
+    let fixture: ComponentFixture<ListboxWithOptions>;
+    let options: DebugElement[];
+    let optionInstances: CdkOption[];
+    let optionElements: HTMLElement[];
+
+    beforeEach(async(() => {
+      TestBed.configureTestingModule({
+        imports: [CdkListboxModule],
+        declarations: [ListboxWithOptions],
+      }).compileComponents();
+    }));
+
+    beforeEach(async(() => {
+      fixture = TestBed.createComponent(ListboxWithOptions);
+      fixture.detectChanges();
+
+      options = fixture.debugElement.queryAll(By.directive(CdkOption));
+      optionInstances = options.map(o => o.injector.get<CdkOption>(CdkOption));
+      optionElements = options.map(o => o.nativeElement);
+    }));
+
+    it('should generate a unique optionId for each option', () => {
+      let optionIds: string[] = [];
+      for (const instance of optionInstances) {
+        expect(optionIds.indexOf(instance.id)).toBe(-1);
+        optionIds.push(instance.id);
+
+        expect(instance.id).toMatch(/cdk-option-\d+/);
+      }
+    });
+
+    it('should have set the selected input of the options to null by default', () => {
+      for (const instance of optionInstances) {
+        expect(instance.selected).toBeFalse();
+      }
+    });
+
+    it('should update aria-selected when selected is changed programmatically', () => {
+      expect(optionElements[0].getAttribute('aria-selected')).toBeNull();
+      optionInstances[1].selected = true;
+      fixture.detectChanges();
+
+      expect(optionElements[1].getAttribute('aria-selected')).toBe('true');
+    });
+
+    it('should update selected option on click event', () => {
+      let selectedOptions = optionInstances.filter(option => option.selected);
+
+      expect(selectedOptions.length).toBe(0);
+      expect(optionElements[0].getAttribute('aria-selected')).toBeNull();
+      expect(optionInstances[0].selected).toBeFalse();
+      expect(fixture.componentInstance.changedOption).toBeUndefined();
+
+      dispatchMouseEvent(optionElements[0], 'click');
+      fixture.detectChanges();
+
+      selectedOptions = optionInstances.filter(option => option.selected);
+      expect(selectedOptions.length).toBe(1);
+      expect(optionElements[0].getAttribute('aria-selected')).toBe('true');
+      expect(optionInstances[0].selected).toBeTrue();
+      expect(fixture.componentInstance.changedOption).toBeDefined();
+      expect(fixture.componentInstance.changedOption.id).toBe(optionInstances[0].id);
+    });
+  });
+
+});
+
+@Component({
+  template: `
+  <div cdkListbox (selectionChange)="onSelectionChange($event)">
+    <div cdkOption>Void</div>
+    <div cdkOption>Solar</div>
+    <div cdkOption>Arc</div>
+    <div cdkOption>Stasis</div>
+  </div>`
+})
+class ListboxWithOptions {
+  changedOption: CdkOption;
+
+  onSelectionChange(event: ListboxSelectionChangeEvent) {
+    this.changedOption = event.option;
+  }
+}

src/cdk-experimental/listbox/listbox.ts

@@ -6,19 +6,63 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Directive} from '@angular/core';
+import {
+  ContentChildren,
+  Directive,
+  EventEmitter, forwardRef, Inject,
+  Input, Output,
+  QueryList
+} from '@angular/core';
+import {BooleanInput, coerceBooleanProperty} from '@angular/cdk/coercion';
 
+let nextId = 0;
+
+/**
+ * Directive that applies interaction patterns to an element following the aria role of option.
+ * Typically meant to be placed inside a listbox. Logic handling selection, disabled state, and
+ * value is built in.
+ */
 @Directive({
   selector: '[cdkOption]',
   exportAs: 'cdkOption',
   host: {
     role: 'option',
+    '(click)': 'toggle()',
+    '[attr.aria-selected]': 'selected || null',
+    '[id]': 'id',
   }
 })
 export class CdkOption {
+  private _selected: boolean = false;
+
+  /** Whether the option is selected or not */
+  @Input()
+  get selected(): boolean {
+    return this._selected;
+  }
+  set selected(value: boolean) {
+    this._selected = coerceBooleanProperty(value);
+  }
 
+  /** The id of the option, set to a uniqueid if the user does not provide one */
+  @Input() id = `cdk-option-${nextId++}`;
+
+  constructor(@Inject(forwardRef(() => CdkListbox)) public listbox: CdkListbox) {}
+
+  /** Toggles the selected state, emits a change event through the injected listbox */
+  toggle() {
+    this.selected = !this.selected;
+    this.listbox._emitChangeEvent(this);
+  }
+
+  static ngAcceptInputType_selected: BooleanInput;
 }
 
+/**
+ * Directive that applies interaction patterns to an element following the aria role of listbox.
+ * Typically CdkOption elements are placed inside the listbox. Logic to handle keyboard navigation,
+ * selection of options, active options, and disabled states is built in.
+ */
 @Directive({
   selector: '[cdkListbox]',
   exportAs: 'cdkListbox',
@@ -28,4 +72,33 @@ export class CdkOption {
 })
 export class CdkListbox {
 
+  /** A query list containing all CdkOption elements within this listbox */
+  @ContentChildren(CdkOption, {descendants: true}) _options: QueryList<CdkOption>;
+
+  @Output() readonly selectionChange: EventEmitter<ListboxSelectionChangeEvent> =
+      new EventEmitter<ListboxSelectionChangeEvent>();
+
+  /** Emits a selection change event, called when an option has its selected state changed */
+  _emitChangeEvent(option: CdkOption) {
+    this.selectionChange.emit(new ListboxSelectionChangeEvent(this, option));
+  }
+
+  /** Sets the given option's selected state to true */
+  select(option: CdkOption) {
+    option.selected = true;
+  }
+
+  /** Sets the given option's selected state to null. Null is preferable for screen readers */
+  deselect(option: CdkOption) {
+    option.selected = false;
+  }
+}
+
+/** Change event that is being fired whenever the selected state of an option changes. */
+export class ListboxSelectionChangeEvent {
+  constructor(
+    /** Reference to the listbox that emitted the event. */
+    public source: CdkListbox,
+    /** Reference to the option that has been changed. */
+    public option: CdkOption) {}
 }