From 63f7e336dbdf4bcbd456ff0180e79436ecbe69c2 Mon Sep 17 00:00:00 2001
From: Neeraj P Yetheendran <neeraj.yathy@gmail.com>
Date: Fri, 8 Mar 2024 19:00:56 +0530
Subject: [PATCH] Create new Stimulus KeyboardController (w-kbd)

---
 .../controllers/KeyboardController.stories.js |  59 ++++++++
 .../controllers/KeyboardController.test.js    | 129 ++++++++++++++++++
 client/src/controllers/KeyboardController.ts  |  55 ++++++++
 client/src/controllers/index.ts               |   2 +
 4 files changed, 245 insertions(+)
 create mode 100644 client/src/controllers/KeyboardController.stories.js
 create mode 100644 client/src/controllers/KeyboardController.test.js
 create mode 100644 client/src/controllers/KeyboardController.ts

diff --git a/client/src/controllers/KeyboardController.stories.js b/client/src/controllers/KeyboardController.stories.js
new file mode 100644
index 0000000000..7d5bcc784e
--- /dev/null
+++ b/client/src/controllers/KeyboardController.stories.js
@@ -0,0 +1,59 @@
+import React, { useState } from 'react';
+
+import { StimulusWrapper } from '../../storybook/StimulusWrapper';
+import { KeyboardController } from './KeyboardController';
+
+export default {
+  title: 'Stimulus / KeyboardController',
+  argTypes: {
+    debug: { control: 'boolean', defaultValue: false },
+  },
+};
+
+const definitions = [
+  { identifier: 'w-kbd', controllerConstructor: KeyboardController },
+];
+
+const Template = ({ debug = false }) => {
+  const [count, setCount] = useState(0);
+  return (
+    <StimulusWrapper debug={debug} definitions={definitions}>
+      <button
+        type="button"
+        className="button button-small button-secondary"
+        data-controller="w-kbd"
+        data-w-kbd-key-value="mod+j"
+        onClick={() => {
+          setCount((stateCount) => stateCount + 1);
+        }}
+      >
+        Add to count
+      </button>
+      <button
+        type="button"
+        className="button button-small button-secondary"
+        data-controller="w-kbd"
+        aria-keyshortcuts=";"
+        onClick={() => {
+          setCount(0);
+        }}
+      >
+        Clear count
+      </button>
+      <div>
+        <p>
+          Add to count with <kbd> Command ⌘</kbd> + <kbd>j</kbd> on macOS or{' '}
+          <kbd>Ctrl</kbd> + <kbd>j</kbd> on Windows.
+        </p>
+        <p>
+          Clear found with <kbd>;</kbd>
+        </p>
+      </div>
+      <p id="counter">
+        Click count: <strong>{count}</strong>
+      </p>
+    </StimulusWrapper>
+  );
+};
+
+export const Base = Template.bind({});
diff --git a/client/src/controllers/KeyboardController.test.js b/client/src/controllers/KeyboardController.test.js
new file mode 100644
index 0000000000..acf8d65d1a
--- /dev/null
+++ b/client/src/controllers/KeyboardController.test.js
@@ -0,0 +1,129 @@
+import { Application } from '@hotwired/stimulus';
+import Mousetrap from 'mousetrap';
+
+import { KeyboardController } from './KeyboardController';
+
+describe('KeyboardController', () => {
+  let app;
+  const buttonClickMock = jest.fn();
+
+  /**
+   * Simulates a keydown, keypress, and keyup event for the provided key.
+   */
+  const simulateKey = (
+    { key, which = key.charCodeAt(0), ctrlKey = false, metaKey = false },
+    target = document.body,
+  ) =>
+    Object.fromEntries(
+      ['keydown', 'keypress', 'keyup'].map((type) => [
+        type,
+        target.dispatchEvent(
+          new KeyboardEvent(type, {
+            bubbles: true,
+            cancelable: true,
+            key: key,
+            which,
+            ctrlKey,
+            metaKey,
+          }),
+        ),
+      ]),
+    );
+
+  const setup = async (html) => {
+    document.body.innerHTML = `<main>${html}</main>`;
+
+    app = Application.start();
+    app.register('w-kbd', KeyboardController);
+
+    await Promise.resolve();
+  };
+
+  beforeAll(() => {
+    HTMLButtonElement.prototype.click = buttonClickMock;
+  });
+
+  afterEach(() => {
+    app?.stop();
+    jest.clearAllMocks();
+    Mousetrap.reset();
+  });
+
+  describe('basic keyboard shortcut usage', () => {
+    it('should call the click event when the `j` key is pressed after being registered', async () => {
+      expect(buttonClickMock).not.toHaveBeenCalled();
+
+      await setup(
+        `<button id="btn" data-controller="w-kbd" data-w-kbd-key-value="j">Go</button>`,
+      );
+
+      // Simulate the keydown event & check that the default was prevented
+      expect(simulateKey({ key: 'j' })).toHaveProperty('keypress', false);
+
+      expect(buttonClickMock).toHaveBeenCalledTimes(1);
+      expect(buttonClickMock.mock.contexts).toEqual([
+        document.getElementById('btn'),
+      ]);
+    });
+
+    it('should call the click event when `ctrl+j` is pressed after being registered', async () => {
+      expect(buttonClickMock).not.toHaveBeenCalled();
+
+      await setup(
+        `<button id="btn" data-controller="w-kbd" data-w-kbd-key-value="ctrl+j">Go</button>`,
+      );
+
+      simulateKey({ key: 'j', which: 74, ctrlKey: true });
+
+      expect(buttonClickMock).toHaveBeenCalledTimes(1);
+      expect(buttonClickMock.mock.contexts).toEqual([
+        document.getElementById('btn'),
+      ]);
+    });
+
+    it('should call the click event when `command+j` is pressed after being registered', async () => {
+      expect(buttonClickMock).not.toHaveBeenCalled();
+
+      await setup(
+        `<button id="btn" data-controller="w-kbd" data-w-kbd-key-value="command+j">Go</button>`,
+      );
+
+      simulateKey({ key: 'j', which: 74, metaKey: true });
+
+      expect(buttonClickMock).toHaveBeenCalledTimes(1);
+      expect(buttonClickMock.mock.contexts).toEqual([
+        document.getElementById('btn'),
+      ]);
+    });
+
+    it('should call the click event when `mod+j` is pressed after being registered', async () => {
+      expect(buttonClickMock).not.toHaveBeenCalled();
+
+      await setup(
+        `<button id="btn" data-controller="w-kbd" data-w-kbd-key-value="mod+j">Go</button>`,
+      );
+
+      simulateKey({ key: 'j', which: 74, metaKey: true });
+      simulateKey({ key: 'j', which: 74, ctrlKey: true });
+
+      expect(buttonClickMock).toHaveBeenCalledTimes(1);
+      expect([buttonClickMock.mock.contexts[0]]).toEqual([
+        document.getElementById('btn'),
+      ]);
+    });
+  });
+
+  describe('aria-keyshortcuts usage', () => {
+    it('should take the aria-keyshortcuts attribute if the data-w-kbd-key-value is not set', async () => {
+      expect(buttonClickMock).not.toHaveBeenCalled();
+
+      await setup(
+        `<button id="btn" data-controller="w-kbd" aria-keyshortcuts="l">Go</button>`,
+      );
+
+      simulateKey({ key: 'l' });
+
+      expect(buttonClickMock).toHaveBeenCalledTimes(1);
+    });
+  });
+});
diff --git a/client/src/controllers/KeyboardController.ts b/client/src/controllers/KeyboardController.ts
new file mode 100644
index 0000000000..f8c1b8c0ec
--- /dev/null
+++ b/client/src/controllers/KeyboardController.ts
@@ -0,0 +1,55 @@
+import { Controller } from '@hotwired/stimulus';
+import Mousetrap from 'mousetrap';
+
+/**
+ * Adds the ability to trigger a button click event using a
+ * keyboard shortcut declared on the controlled element.
+ *
+ * @see https://craig.is/killing/mice
+ *
+ * @example
+ * ```html
+ * <button type="button" data-controller="w-kbd" data-w-kbd-key="[">Trigger me with the <kbd>[</kbd> key.</button>
+ * ```
+ *
+ * @example - use aria-keyshortcuts (when the key string is compatible with Mousetrap's syntax)
+ * @see https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-keyshortcuts
+ * ```html
+ * <button type="button" data-controller="w-kbd" aria-keyshortcuts="alt+p">Trigger me with alt+p.</button>
+ * ```
+ */
+export class KeyboardController extends Controller<
+  HTMLButtonElement | HTMLAnchorElement
+> {
+  static values = { key: { default: '', type: String } };
+
+  /** Keyboard shortcut string. */
+  declare keyValue: string;
+
+  initialize() {
+    this.handleKey = this.handleKey.bind(this);
+    if (!this.keyValue) {
+      const ariaKeyShortcuts = this.element.getAttribute('aria-keyshortcuts');
+      if (ariaKeyShortcuts) {
+        this.keyValue = ariaKeyShortcuts;
+      }
+    }
+  }
+
+  handleKey(event: Event) {
+    if (event.preventDefault) event.preventDefault();
+    this.element.click();
+  }
+
+  /**
+   * When a key is set or changed, bind the handler to the keyboard shortcut.
+   * This will override the shortcut, if already set.
+   */
+  keyValueChanged(key: string, previousKey: string) {
+    if (previousKey && previousKey !== key) {
+      Mousetrap.unbind(previousKey);
+    }
+
+    Mousetrap.bind(key, this.handleKey);
+  }
+}
diff --git a/client/src/controllers/index.ts b/client/src/controllers/index.ts
index 1a19366bb8..e2b50a5737 100644
--- a/client/src/controllers/index.ts
+++ b/client/src/controllers/index.ts
@@ -13,6 +13,7 @@ import { DismissibleController } from './DismissibleController';
 import { DrilldownController } from './DrilldownController';
 import { DropdownController } from './DropdownController';
 import { InitController } from './InitController';
+import { KeyboardController } from './KeyboardController';
 import { LinkController } from './LinkController';
 import { OrderableController } from './OrderableController';
 import { ProgressController } from './ProgressController';
@@ -46,6 +47,7 @@ export const coreControllerDefinitions: Definition[] = [
   { controllerConstructor: DrilldownController, identifier: 'w-drilldown' },
   { controllerConstructor: DropdownController, identifier: 'w-dropdown' },
   { controllerConstructor: InitController, identifier: 'w-init' },
+  { controllerConstructor: KeyboardController, identifier: 'w-kbd' },
   { controllerConstructor: LinkController, identifier: 'w-link' },
   { controllerConstructor: OrderableController, identifier: 'w-orderable' },
   { controllerConstructor: ProgressController, identifier: 'w-progress' },