Introduce behaviors

.changeset/serious-flowers-try.md

@@ -0,0 +1,5 @@
+---
+'@chialab/loock': major
+---
+
+Introduce focus and keyboard navigation behaviors.

README.md

@@ -37,21 +37,19 @@ yarn add @chialab/loock
 ### CDN
 
 ```ts
-import { FocusContext } from 'https://unpkg.com/@chialab/loock?module';
+import { focusTrapBehavior } from 'https://unpkg.com/@chialab/loock?module';
 ```
 
 ## Usage
 
 ```ts
-import { FocusContext } from '@chialab/loock';
+import { focusTrapBehavior } from '@chialab/loock';
 
 const dialog = document.getElementById('.dialog');
-// define a context
-const dialogContext = new FocusContext(dialog);
+const trap = focusTrapBehavior(dialog);
 
 dialog.addEventListener('open', () => {
-    // activate the context
-    dialogContext.enter();
+    trap.connect();
 });
 ```
 

index.html

@@ -59,16 +59,16 @@ <h1 class="text-3xl font-bold">Loock</h1>
                         src="https://demo.chialab.io/catalog/media/moon/Apollo_11_Intro.mp4"></video>
                 </section>
                 <script type="module">
-                    import { FocusContext } from '/src/index.ts';
+                    import { focusTrapBehavior } from '/src/index.ts';
 
                     const article1 = document.querySelector('#article1');
                     const button1 = article1.querySelector('header button');
                     const section1 = article1.querySelector('section');
-                    const context1 = new FocusContext(section1);
+                    const behavior1 = focusTrapBehavior(section1);
 
                     button1.addEventListener('click', () => {
                         button1.focus();
-                        context1.enter();
+                        behavior1.connect();
                     });
                 </script>
             </article>
@@ -145,18 +145,18 @@ <h1 class="text-3xl font-bold">Loock</h1>
                 </section>
                 <code class="text-xs">{ focusContainer: true }</code>
                 <script type="module">
-                    import { FocusContext } from '/src/index.ts';
+                    import { focusTrapBehavior } from '/src/index.ts';
 
                     const article2 = document.querySelector('#article2');
                     const button2 = article2.querySelector('header button');
                     const section2 = article2.querySelector('section');
-                    const context2 = new FocusContext(section2, {
+                    const behavior2 = focusTrapBehavior(section2, {
                         focusContainer: true,
                     });
 
                     button2.addEventListener('click', () => {
                         button2.focus();
-                        context2.enter();
+                        behavior2.connect();
                     });
                 </script>
             </article>
@@ -208,14 +208,14 @@ <h2 class="text-2xl font-bold">Dialog</h2>
                 </section>
                 <code class="text-xs">{ inert: true }</code>
                 <script type="module">
-                    import { FocusContext } from './src/index.ts';
+                    import { focusTrapBehavior } from './src/index.ts';
 
                     const article3 = document.querySelector('#article3');
                     const section3 = article3.querySelector('section');
                     const button3 = section3.querySelector('button');
                     const dialog = section3.querySelector('dialog');
 
-                    const context3 = new FocusContext(dialog.querySelector('.dialog-content'), {
+                    const behavior3 = focusTrapBehavior(dialog.querySelector('.dialog-content'), {
                         inert: true,
                         onExit: () => {
                             dialog.close();
@@ -224,7 +224,7 @@ <h2 class="text-2xl font-bold">Dialog</h2>
                     button3.addEventListener('click', () => {
                         button3.focus();
                         dialog.showModal();
-                        context3.enter();
+                        behavior3.connect();
                     });
                 </script>
             </article>

src/constants.ts

@@ -0,0 +1,31 @@
+/**
+ * Default focusable selectors.
+ */
+export const DEFAULT_SELECTORS = [
+    'a[href]',
+    'area[href]',
+    'button',
+    'input',
+    'select',
+    'textarea',
+    'video[controls]',
+    'audio[controls]',
+    'embed',
+    'iframe',
+    'summary',
+    '[contenteditable]',
+    '[tabindex]',
+];
+
+/**
+ * Default ignore selectors.
+ */
+export const DEFAULT_IGNORE_SELECTORS = [
+    '[tabindex="-1"]',
+    '[disabled]',
+    '[hidden]',
+    '[aria-hidden="true"]',
+    '[aria-disabled="true"]',
+    '[inert]',
+    'details:not([open]) *:not(summary)',
+];

src/findFocusableChildren.ts

@@ -0,0 +1,36 @@
+import { DEFAULT_IGNORE_SELECTORS, DEFAULT_SELECTORS } from './constants';
+
+/**
+ * Find all focusable children of a node.
+ * @param node The target node.
+ * @param include The selectors to include.
+ * @param exclude The selectors to exclude.
+ * @returns The focusable children list.
+ */
+export function findFocusableChildren(
+    node: Element,
+    include: string[] = DEFAULT_SELECTORS,
+    exclude: string[] = DEFAULT_IGNORE_SELECTORS
+) {
+    return (Array.from(node.querySelectorAll(include.join(', '))) as HTMLElement[]).filter((element) => {
+        if (exclude.some((selector) => element.matches(selector))) {
+            return false;
+        }
+
+        if (element.tagName === 'INPUT' && (element as HTMLInputElement).type === 'radio') {
+            const name = (element as HTMLInputElement).name;
+            const inputs = node.querySelectorAll(`input[type="radio"][name="${name}"]`);
+            const checked = Array.from(inputs).find((input) => (input as HTMLInputElement).checked);
+            if (checked) {
+                if (checked !== element) {
+                    return false;
+                }
+            } else if (element !== inputs[0]) {
+                return false;
+            }
+        }
+
+        const { width, height } = element.getBoundingClientRect();
+        return !!height && !!width;
+    });
+}

src/focusEnterBehavior.ts

@@ -0,0 +1,74 @@
+/**
+ * The focus enter options.
+ */
+export interface FocusEnterOptions {
+    /**
+     * The callback when focus enter.
+     */
+    onEnter: (element: Element) => void;
+    /**
+     * The callback when focus exit.
+     */
+    onExit: () => void;
+}
+
+/**
+ * Focus first option on focus enter.
+ * @param element The target element.
+ * @param options The options.
+ * @returns The behavior controller.
+ */
+export function focusEnterBehavior(element: HTMLElement, options: FocusEnterOptions) {
+    const document = element.ownerDocument;
+    const { onEnter, onExit } = options;
+    let focused = false;
+    let connected = false;
+
+    const onFocusIn = () => {
+        const activeElement = document.activeElement;
+        if (focused || !activeElement) {
+            return;
+        }
+
+        focused = true;
+        onEnter(activeElement);
+    };
+
+    const onFocusOut = () => {
+        if (!focused) {
+            return;
+        }
+
+        setTimeout(() => {
+            const activeElement = document.activeElement;
+            if (element !== activeElement && !element.contains(activeElement)) {
+                focused = false;
+                onExit();
+            }
+        });
+    };
+
+    return {
+        get connected() {
+            return connected;
+        },
+        connect() {
+            if (connected) {
+                return;
+            }
+            connected = true;
+            focused = false;
+            element.addEventListener('focusin', onFocusIn);
+            element.addEventListener('focusout', onFocusOut);
+        },
+        disconnect() {
+            if (!connected) {
+                return;
+            }
+            connected = false;
+            focused = false;
+            element.removeEventListener('focusin', onFocusIn);
+            element.removeEventListener('focusout', onFocusOut);
+        },
+    };
+}

src/focusFirstChildBehavior.ts

@@ -0,0 +1,69 @@
+import { findFocusableChildren } from './findFocusableChildren';
+
+/**
+ * The options for focus first option on focus enter.
+ */
+export interface FocusFirstChildOptions {
+    /**
+     * The focusable elements.
+     */
+    elements?: HTMLElement[];
+    /**
+     * The selectors for focusable nodes.
+     */
+    include?: string[];
+    /**
+     * The selectors for ignored nodes.
+     */
+    exclude?: string[];
+}
+
+/**
+ * Focus first option on focus enter.
+ * @param element The target element.
+ * @param options The options.
+ * @returns The behavior controller.
+ */
+export function focusFirstChildBehavior(element: HTMLElement, options: FocusFirstChildOptions = {}) {
+    const document = element.ownerDocument;
+    let activeElement: HTMLElement | null = null;
+    let connected = false;
+
+    const onFocus = () => {
+        const { include, exclude, elements = findFocusableChildren(element, include, exclude) } = options;
+        const target = document.activeElement as HTMLElement;
+        if (target === element) {
+            if (activeElement && element.contains(activeElement)) {
+                activeElement.focus();
+                return;
+            }
+
+            elements[0]?.focus();
+            return;
+        } else if (elements.includes(target)) {
+            activeElement = target;
+        }
+    };
+
+    return {
+        get connected() {
+            return connected;
+        },
+        connect() {
+            if (connected) {
+                return;
+            }
+            connected = true;
+            activeElement = null;
+            element.addEventListener('focus', onFocus, true);
+        },
+        disconnect() {
+            if (!connected) {
+                return;
+            }
+            connected = false;
+            activeElement = null;
+            element.removeEventListener('focus', onFocus, true);
+        },
+    };
+}