feat: improve focus behavior on terms

diplodoc-platform · Aug 19, 2024 · a64f1ec · a64f1ec
1 parent c81ad73
commit a64f1ec
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Showing 3 changed files with 130 additions and 49 deletions.
diff --git a/src/js/term/index.ts b/src/js/term/index.ts
@@ -1,81 +1,50 @@
+import {getEventTarget, isCustom} from '../utils';
 import {
-    Selector,
     closeDefinition,
-    createDefinitionElement,
     openClass,
+    openDefinition,
     openDefinitionClass,
-    setDefinitionId,
     setDefinitionPosition,
-    setDefinitonAriaLive,
 } from './utils';
-import {getEventTarget, isCustom} from '../utils';
 
 if (typeof document !== 'undefined') {
     document.addEventListener('click', (event) => {
-        const openDefinition = document.getElementsByClassName(
-            openDefinitionClass,
-        )[0] as HTMLElement;
-        const target = getEventTarget(event) as HTMLElement;
-
-        const termId = target.getAttribute('id');
-        const termKey = target.getAttribute('term-key');
-        let definitionElement = document.getElementById(termKey + '_element');
-
-        if (termKey && !definitionElement) {
-            definitionElement = createDefinitionElement(target);
-        }
-
-        const isSameTerm = openDefinition && termId === openDefinition.getAttribute('term-id');
-        if (isSameTerm) {
-            closeDefinition(openDefinition);
-            return;
-        }
-
-        const isTargetDefinitionContent = target.closest(
-            [Selector.CONTENT.replace(' ', ''), openClass].join('.'),
-        );
-
-        if (openDefinition && !isTargetDefinitionContent) {
-            closeDefinition(openDefinition);
-        }
-
-        if (isCustom(event) || !target.matches(Selector.TITLE) || !definitionElement) {
-            return;
+        if (getEventTarget(event) || !isCustom(event)) {
+            openDefinition(getEventTarget(event) as HTMLElement);
         }
-
-        setDefinitionId(definitionElement, target);
-        setDefinitonAriaLive(definitionElement, target);
-        setDefinitionPosition(definitionElement, target);
-
-        definitionElement.classList.toggle(openClass);
     });
 
     document.addEventListener('keydown', (event) => {
-        const openDefinition = document.getElementsByClassName(
+        const openedDefinition = document.getElementsByClassName(
             openDefinitionClass,
         )[0] as HTMLElement;
-        if (event.key === 'Escape' && openDefinition) {
-            closeDefinition(openDefinition);
+
+        if (event.key === 'Enter' && document.activeElement) {
+            openDefinition(document.activeElement as HTMLElement);
+        }
+
+        if (event.key === 'Escape' && openedDefinition) {
+            closeDefinition(openedDefinition);
         }
     });
 
     window.addEventListener('resize', () => {
-        const openDefinition = document.getElementsByClassName(
+        const openedDefinition = document.getElementsByClassName(
             openDefinitionClass,
         )[0] as HTMLElement;
 
-        if (!openDefinition) {
+        if (!openedDefinition) {
             return;
         }
 
-        const termId = openDefinition.getAttribute('term-id') || '';
+        const termId = openedDefinition.getAttribute('term-id') || '';
         const termElement = document.getElementById(termId);
 
         if (!termElement) {
-            openDefinition.classList.toggle(openClass);
+            openedDefinition.classList.toggle(openClass);
             return;
         }
 
-        setDefinitionPosition(openDefinition, termElement);
+        setDefinitionPosition(openedDefinition, termElement);
     });
 }
diff --git a/src/js/term/utils.ts b/src/js/term/utils.ts
@@ -137,16 +137,95 @@ function termParentElement(term: HTMLElement | null) {
     return closestScrollableParent || term.parentElement;
 }
 
+export function openDefinition(target: HTMLElement) {
+    const openDefinition = document.getElementsByClassName(openDefinitionClass)[0] as HTMLElement;
+
+    const termId = target.getAttribute('id');
+    const termKey = target.getAttribute('term-key');
+    let definitionElement = document.getElementById(termKey + '_element');
+
+    if (termKey && !definitionElement) {
+        definitionElement = createDefinitionElement(target);
+    }
+
+    const isSameTerm = openDefinition && termId === openDefinition.getAttribute('term-id');
+    if (isSameTerm) {
+        closeDefinition(openDefinition);
+        return;
+    }
+
+    const isTargetDefinitionContent = target.closest(
+        [Selector.CONTENT.replace(' ', ''), openClass].join('.'),
+    );
+
+    if (openDefinition && !isTargetDefinitionContent) {
+        closeDefinition(openDefinition);
+    }
+
+    if (!target.matches(Selector.TITLE) || !definitionElement) {
+        return;
+    }
+
+    setDefinitionId(definitionElement, target);
+    setDefinitonAriaLive(definitionElement, target);
+    setDefinitionPosition(definitionElement, target);
+
+    definitionElement.classList.toggle(openClass);
+
+    trapFocus(definitionElement);
+}
+
+export function openDefinition2(target: HTMLElement) {
+    const openDefinition = document.getElementsByClassName(openDefinitionClass)[0] as HTMLElement;
+
+    const termId = target.getAttribute('id');
+    const termKey = target.getAttribute('term-key');
+    let definitionElement = document.getElementById(termKey + '_element');
+
+    if (termKey && !definitionElement) {
+        definitionElement = createDefinitionElement(target);
+    }
+
+    const isSameTerm = openDefinition && termId === openDefinition.getAttribute('term-id');
+    if (isSameTerm) {
+        closeDefinition(openDefinition);
+        return;
+    }
+
+    const isTargetDefinitionContent = target.closest(
+        [Selector.CONTENT.replace(' ', ''), openClass].join('.'),
+    );
+
+    if (openDefinition && !isTargetDefinitionContent) {
+        closeDefinition(openDefinition);
+    }
+
+    if (!target.matches(Selector.TITLE) || !definitionElement) {
+        return;
+    }
+
+    setDefinitionId(definitionElement, target);
+    setDefinitonAriaLive(definitionElement, target);
+    setDefinitionPosition(definitionElement, target);
+
+    definitionElement.classList.toggle(openClass);
+
+    trapFocus(definitionElement);
+}
+
 export function closeDefinition(definition: HTMLElement) {
     definition.classList.remove(openClass);
     const termId = definition.getAttribute('term-id') || '';
-    const termParent = termParentElement(document.getElementById(termId));
+    const term = document.getElementById(termId);
+    const termParent = termParentElement(term);
 
     if (!termParent) {
         return;
     }
 
     termParent.removeEventListener('scroll', termOnResize);
+    term?.focus(); // Set focus back to open button after closing popup
+
     isListenerNeeded = true;
 }
 
@@ -167,3 +246,35 @@ function getCoords(elem: HTMLElement) {
 
     return {top: Math.round(top), left: Math.round(left)};
 }
+
+export function trapFocus(element: HTMLElement) {
+    const focusableElements = element.querySelectorAll(
+        'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])',
+    );
+    const firstFocusableElement = focusableElements[0];
+    const lastFocusableElement = focusableElements[focusableElements.length - 1];
+
+    firstFocusableElement?.focus();
+
+    element.addEventListener('keydown', function (e) {
+        const isTabPressed = e.key === 'Tab' || e.keyCode === 9;
+        if (!isTabPressed) {
+            return;
+        }
+
+        if (e.shiftKey) {
+            // if shift key pressed for shift + tab combination
+            if (document.activeElement === firstFocusableElement) {
+                lastFocusableElement.focus(); // add focus for the last focusable element
+                e.preventDefault();
+            }
+        } else {
+            // if tab key is pressed
+            if (document.activeElement === lastFocusableElement) {
+                // if focused has reached to last focusable element then focus first focusable element after pressing tab
+                firstFocusableElement.focus(); // add focus for the first focusable element
+                e.preventDefault();
+            }
+        }
+    });
+}
diff --git a/src/transform/plugins/term/index.ts b/src/transform/plugins/term/index.ts
@@ -100,6 +100,7 @@ const term: MarkdownItPluginCb = (md, options) => {
                     token.attrSet('class', 'yfm yfm-term_title');
                     token.attrSet('term-key', ':' + termKey);
                     token.attrSet('aria-describedby', ':' + termKey + '_element');
+                    token.attrSet('tabindex', '0');
                     token.attrSet('id', generateID());
                     nodes.push(token);