✨ Implement <Listbox /> component (#76)

* 📦 Use ember-sinon

* ✅ Implement <Listbox> tests

* ✨ Implement <Listbox> component

* ✨ Add basic <Listbox> to dummy app

* ✨ Stub components/modifiers in app

* ♻️ Use isOpen and open setter

Use `isOpen` as the yielded property name

Use a `setter` for this property to ensure state is correct when property is changed externally.

Pass `openListbox` and `closeListbox` actions to components.

* ♻️ Use focus-trap and click-outside

Use `focus-trap` to manage focus when opening/closing the listbox

Use `click-outside` to manage document click events

* ♻️ Use isDisabled property

* ♻️ Allow custom ul tagname

* ♻️ Improve performance when setting a selected option

Now storing the index of each listbox option within the list.

This means we avoid an expensive `find` operation when setting the selected option on mouse click or key event.

* ♻️ Remove ember-sinon dependency

* ♻️ Remove 1px class from listbox

* ♻️ Expose openListbox, closeListbox, isOpen

* ♻️ Remove aria modifier

* ♻️ Option GUID cleanup

* ♻️ find -> forEach

* ♻️ Remove click-outside dependency

* 🚨 Fix linter errors

* ♻️ Remove redundant conditional

* ♻️ Add test todos for hidden render strategy

addon/components/listbox.hbs

@@ -0,0 +1,47 @@
+{{yield
+  (hash
+    isOpen=this.isOpen
+    disabled=this.isDisabled
+    openListbox=this.openListbox
+    closeListbox=this.closeListbox
+    Options=(component
+      'listbox/-options'
+      isOpen=this.isOpen
+      guid=this.guid
+      registerOptionElement=this.registerOptionElement
+      registerOptionsElement=this.registerOptionsElement
+      unregisterOptionsElement=this.unregisterOptionsElement
+      hasLabelElement=this.labelElement
+      activeOptionGuid=this.activeOptionGuid
+      selectedOptionGuid=this.selectedOptionGuid
+      setActiveOption=this.setActiveOption
+      unsetActiveOption=this.unsetActiveOption
+      setSelectedOption=this.setSelectedOption
+      handleKeyPress=this.handleKeyPress
+      handleKeyUp=this.handleKeyUp
+      openListbox=this.openListbox
+      closeListbox=this.closeListbox
+      handleClickOutside=this.handleClickOutside
+    )
+    Button=(component
+      'listbox/-button'
+      guid=this.guid
+      isOpen=this.isOpen
+      registerButtonElement=this.registerButtonElement
+      handleButtonClick=this.handleButtonClick
+      handleKeyPress=this.handleKeyPress
+      handleKeyUp=this.handleKeyUp
+      isDisabled=this.isDisabled
+      openListbox=this.openListbox
+      closeListbox=this.closeListbox
+      optionsElement=this.optionsElement
+    )
+    Label=(component
+      'listbox/-label'
+      guid=this.guid
+      isOpen=this.isOpen
+      registerLabelElement=this.registerLabelElement
+      handleLabelClick=this.handleLabelClick
+    )
+  )
+}}

addon/components/listbox.js

@@ -0,0 +1,298 @@
+import Component from '@glimmer/component';
+import { tracked } from '@glimmer/tracking';
+import { guidFor } from '@ember/object/internals';
+import { action } from '@ember/object';
+import { debounce } from '@ember/runloop';
+
+const ACTIVATE_NONE = 0;
+const ACTIVATE_FIRST = 1;
+const ACTIVATE_LAST = 2;
+
+export default class ListboxComponent extends Component {
+  @tracked activeOptionIndex;
+  activateBehaviour = ACTIVATE_NONE;
+  buttonElement;
+  guid = `${guidFor(this)}-headlessui-listbox`;
+  @tracked _isOpen = this.args.isOpen || false;
+  labelElement;
+  optionsElement;
+  optionElements = [];
+  optionValues = {};
+  search = '';
+  @tracked selectedOptionIndex;
+
+  get activeOptionGuid() {
+    return this.optionElements[this.activeOptionIndex]?.id;
+  }
+
+  get isDisabled() {
+    return !!this.args.disabled;
+  }
+
+  get selectedOptionGuid() {
+    return this.optionElements[this.selectedOptionIndex]?.id;
+  }
+
+  get isOpen() {
+    return this._isOpen;
+  }
+
+  set isOpen(isOpen) {
+    if (isOpen) {
+      this.activeOptionIndex = undefined;
+      this.selectedOptionIndex = undefined;
+      this.optionElements = [];
+      this.optionValues = {};
+      this._isOpen = true;
+    } else {
+      this._isOpen = false;
+    }
+  }
+
+  @action
+  closeListbox() {
+    this.isOpen = false;
+  }
+
+  @action
+  handleButtonClick(e) {
+    if (e.button !== 0) return;
+    this.activateBehaviour = ACTIVATE_NONE;
+    this.isOpen = !this.isOpen;
+  }
+
+  @action
+  handleClickOutside(e) {
+    for (let i = 0; i < e.path?.length; i++) {
+      if (e.path[i] === this.buttonElement) {
+        return true;
+      }
+    }
+
+    this.closeListbox();
+
+    return true;
+  }
+
+  @action
+  handleKeyUp(event) {
+    if (event.key === 'ArrowDown') {
+      if (!this.isOpen) {
+        this.activateBehaviour = ACTIVATE_FIRST;
+        this.isOpen = true;
+      } else {
+        this.setNextOptionActive();
+      }
+    } else if (event.key === 'ArrowRight') {
+      if (this.isOpen) {
+        this.setNextOptionActive();
+      }
+    } else if (event.key === 'ArrowUp') {
+      if (!this.isOpen) {
+        this.activateBehaviour = ACTIVATE_LAST;
+        this.isOpen = true;
+      } else {
+        this.setPreviousOptionActive();
+      }
+    } else if (event.key === 'ArrowLeft') {
+      if (this.isOpen) {
+        this.setPreviousOptionActive();
+      }
+    } else if (event.key === 'Home' || event.key === 'PageUp') {
+      this.setFirstOptionActive();
+    } else if (event.key === 'End' || event.key === 'PageDown') {
+      this.setLastOptionActive();
+    } else if (event.key === 'Escape') {
+      this.isOpen = false;
+    }
+  }
+
+  @action
+  handleKeyPress(event) {
+    if (
+      event.key === 'Enter' ||
+      ((event.key === 'Space' || event.key === ' ') && this.search === '')
+    ) {
+      this.activateBehaviour = ACTIVATE_FIRST;
+      if (this.isOpen) {
+        this.setSelectedOption(event.target, event);
+        this.isOpen = false;
+      } else {
+        this.isOpen = true;
+      }
+    } else if (event.key.length === 1) {
+      this.addSearchCharacter(event.key);
+    }
+  }
+  @action
+  handleLabelClick(e) {
+    e.preventDefault();
+    e.stopPropagation();
+    if (e.ctrlKey || e.button !== 0) return;
+    this.buttonElement.focus();
+  }
+
+  @action
+  openListbox() {
+    this.isOpen = true;
+  }
+
+  @action
+  registerButtonElement(buttonElement) {
+    this.buttonElement = buttonElement;
+  }
+
+  @action
+  registerLabelElement(labelElement) {
+    this.labelElement = labelElement;
+  }
+
+  @action
+  registerOptionElement(optionComponent, optionElement) {
+    this.optionElements.push(optionElement);
+    this.optionValues[optionComponent.guid] = optionComponent.args.value;
+
+    // store the index at which the option appears in the list
+    // so we can avoid a O(n) find operation later
+    optionComponent.index = this.optionElements.length - 1;
+    optionElement.setAttribute('data-index', this.optionElements.length - 1);
+
+    if (this.args.value) {
+      if (this.args.value === optionComponent.args.value) {
+        this.selectedOptionIndex = this.activeOptionIndex =
+          this.optionElements.length - 1;
+      }
+    }
+
+    if (!this.selectedOptionIndex) {
+      switch (this.activateBehaviour) {
+        case ACTIVATE_FIRST:
+          this.setFirstOptionActive();
+          break;
+        case ACTIVATE_LAST:
+          this.setLastOptionActive();
+          break;
+      }
+    }
+  }
+
+  @action
+  registerOptionsElement(optionsElement) {
+    this.optionsElement = optionsElement;
+  }
+
+  @action
+  setActiveOption(optionComponent) {
+    this.optionElements.forEach((o, i) => {
+      if (o.id === optionComponent.guid && !o.hasAttribute('disabled')) {
+        this.activeOptionIndex = i;
+        document.querySelector('#' + optionComponent.guid).focus();
+      }
+    });
+  }
+
+  @action
+  setSelectedOption(optionComponent, e) {
+    let optionIndex, optionValue;
+
+    if (optionComponent.constructor.name === 'ListboxOptionComponent') {
+      optionValue = optionComponent.args.value;
+      optionIndex = optionComponent.index;
+    } else if (this.activeOptionIndex !== undefined) {
+      optionValue =
+        this.optionValues[this.optionElements[this.activeOptionIndex].id];
+      optionIndex = parseInt(
+        this.optionElements[this.activeOptionIndex].getAttribute('data-index')
+      );
+    } else {
+      return;
+    }
+
+    if (!this.optionElements[optionIndex].hasAttribute('disabled')) {
+      this.selectedOptionIndex = optionIndex;
+
+      if (this.args.onChange) {
+        this.args.onChange(optionValue);
+      }
+
+      if (e.type === 'click') {
+        this.isOpen = false;
+      }
+    } else {
+      this.optionsElement.focus();
+    }
+  }
+
+  @action
+  unregisterOptionsElement() {
+    this.optionsElement = undefined;
+  }
+
+  @action
+  unsetActiveOption() {
+    this.activeOptionIndex = undefined;
+  }
+
+  setNextOptionActive() {
+    for (
+      let i = this.activeOptionIndex + 1;
+      i < this.optionElements.length;
+      i++
+    ) {
+      if (!this.optionElements[i].hasAttribute('disabled')) {
+        this.activeOptionIndex = i;
+        break;
+      }
+    }
+  }
+
+  setPreviousOptionActive() {
+    for (let i = this.activeOptionIndex - 1; i >= 0; i--) {
+      if (!this.optionElements[i].hasAttribute('disabled')) {
+        this.activeOptionIndex = i;
+        break;
+      }
+    }
+  }
+
+  setFirstOptionActive() {
+    for (let i = 0; i < this.optionElements.length; i++) {
+      if (!this.optionElements[i].hasAttribute('disabled')) {
+        this.activeOptionIndex = i;
+        break;
+      }
+    }
+  }
+
+  setLastOptionActive() {
+    for (let i = this.optionElements.length - 1; i >= 0; i--) {
+      if (!this.optionElements[i].hasAttribute('disabled')) {
+        this.activeOptionIndex = i;
+        break;
+      }
+    }
+  }
+
+  clearSearch() {
+    this.search = '';
+  }
+
+  addSearchCharacter(key) {
+    debounce(this, this.clearSearch, 500);
+
+    this.search += key.toLowerCase();
+
+    for (let i = 0; i < this.optionElements.length; i++) {
+      if (
+        !this.optionElements[i].hasAttribute('disabled') &&
+        this.optionElements[i].textContent
+          .trim()
+          .toLowerCase()
+          .startsWith(this.search)
+      ) {
+        this.activeOptionIndex = i;
+        break;
+      }
+    }
+  }
+}

addon/components/listbox/-button.hbs

@@ -0,0 +1,18 @@
+{{#let (element (or @as 'button')) as |Tag|}}
+  <Tag
+    role={{if @role @role 'button'}}
+    id='{{@guid}}-button'
+    aria-haspopup='listbox'
+    aria-controls={{@guid}}
+    aria-labelledby='{{@guid}}-label {{@guid}}-button'
+    {{on 'click' @handleButtonClick}}
+    {{on 'keyup' @handleKeyUp}}
+    {{on 'keypress' @handleKeyPress}}
+    aria-expanded={{unless @isDisabled (if @isOpen 'true' 'false')}}
+    disabled={{@isDisabled}}
+    {{did-insert @registerButtonElement}}
+    ...attributes
+  >
+    {{yield}}
+  </Tag>
+{{/let}}

addon/components/listbox/-label.hbs

@@ -0,0 +1,11 @@
+{{#let (element (or @as 'label')) as |Tag|}}
+  <Tag
+    id='{{@guid}}-label'
+    for='{{@guid}}-button'
+    {{on 'click' @handleLabelClick}}
+    {{did-insert @registerLabelElement}}
+    ...attributes
+  >
+    {{yield}}
+  </Tag>
+{{/let}}