Merge pull request #4636 from matrix-org/t3chguy/emojipickera11y

Improve accessibility of the emoji picker

src/components/views/emojipicker/Category.js

@@ -67,7 +67,13 @@ class Category extends React.PureComponent {
         const localScrollTop = Math.max(0, scrollTop - listTop);
 
         return (
-            <section className="mx_EmojiPicker_category" data-category-id={this.props.id}>
+            <section
+                id={`mx_EmojiPicker_category_${this.props.id}`}
+                className="mx_EmojiPicker_category"
+                data-category-id={this.props.id}
+                role="tabpanel"
+                aria-label={name}
+            >
                 <h2 className="mx_EmojiPicker_category_label">
                     {name}
                 </h2>

src/components/views/emojipicker/Emoji.js

@@ -16,6 +16,7 @@ limitations under the License.
 
 import React from 'react';
 import PropTypes from 'prop-types';
+import {MenuItem} from "../../structures/ContextMenu";
 
 class Emoji extends React.PureComponent {
     static propTypes = {
@@ -30,14 +31,18 @@ class Emoji extends React.PureComponent {
         const { onClick, onMouseEnter, onMouseLeave, emoji, selectedEmojis } = this.props;
         const isSelected = selectedEmojis && selectedEmojis.has(emoji.unicode);
         return (
-            <li onClick={() => onClick(emoji)}
+            <MenuItem
+                element="li"
+                onClick={() => onClick(emoji)}
                 onMouseEnter={() => onMouseEnter(emoji)}
                 onMouseLeave={() => onMouseLeave(emoji)}
-                className="mx_EmojiPicker_item_wrapper">
+                className="mx_EmojiPicker_item_wrapper"
+                label={emoji.unicode}
+            >
                 <div className={`mx_EmojiPicker_item ${isSelected ? 'mx_EmojiPicker_item_selected' : ''}`}>
                     {emoji.unicode}
                 </div>
-            </li>
+            </MenuItem>
         );
     }
 }

src/components/views/emojipicker/EmojiPicker.js

@@ -147,8 +147,12 @@ class EmojiPicker extends React.Component {
             // We update this here instead of through React to avoid re-render on scroll.
             if (cat.visible) {
                 cat.ref.current.classList.add("mx_EmojiPicker_anchor_visible");
+                cat.ref.current.setAttribute("aria-selected", true);
+                cat.ref.current.setAttribute("tabindex", 0);
             } else {
                 cat.ref.current.classList.remove("mx_EmojiPicker_anchor_visible");
+                cat.ref.current.setAttribute("aria-selected", false);
+                cat.ref.current.setAttribute("tabindex", -1);
             }
         }
     }

src/components/views/emojipicker/Header.js

@@ -16,23 +16,89 @@ limitations under the License.
 
 import React from 'react';
 import PropTypes from 'prop-types';
+import classNames from "classnames";
+
+import {_t} from "../../../languageHandler";
+import {Key} from "../../../Keyboard";
 
 class Header extends React.PureComponent {
     static propTypes = {
         categories: PropTypes.arrayOf(PropTypes.object).isRequired,
         onAnchorClick: PropTypes.func.isRequired,
-        refs: PropTypes.object,
+    };
+
+    findNearestEnabled(index, delta) {
+        index += this.props.categories.length;
+        const cats = [...this.props.categories, ...this.props.categories, ...this.props.categories];
+
+        while (index < cats.length && index >= 0) {
+            if (cats[index].enabled) return index % this.props.categories.length;
+            index += delta > 0 ? 1 : -1;
+        }
+    }
+
+    changeCategoryRelative(delta) {
+        const current = this.props.categories.findIndex(c => c.visible);
+        this.changeCategoryAbsolute(current + delta, delta);
+    }
+
+    changeCategoryAbsolute(index, delta=1) {
+        const category = this.props.categories[this.findNearestEnabled(index, delta)];
+        if (category) {
+            this.props.onAnchorClick(category.id);
+            category.ref.current.focus();
+        }
+    }
+
+    // Implements ARIA Tabs with Automatic Activation pattern
+    // https://www.w3.org/TR/wai-aria-practices/examples/tabs/tabs-1/tabs.html
+    onKeyDown = (ev) => {
+        let handled = true;
+        switch (ev.key) {
+            case Key.ARROW_LEFT:
+                this.changeCategoryRelative(-1);
+                break;
+            case Key.ARROW_RIGHT:
+                this.changeCategoryRelative(1);
+                break;
+
+            case Key.HOME:
+                this.changeCategoryAbsolute(0);
+                break;
+            case Key.END:
+                this.changeCategoryAbsolute(this.props.categories.length - 1, -1);
+                break;
+            default:
+                handled = false;
+        }
+
+        if (handled) {
+            ev.preventDefault();
+            ev.stopPropagation();
+        }
     };
 
     render() {
         return (
-            <nav className="mx_EmojiPicker_header">
-                {this.props.categories.map(category => (
-                    <button disabled={!category.enabled} key={category.id} ref={category.ref}
-                        className={`mx_EmojiPicker_anchor ${category.visible ? 'mx_EmojiPicker_anchor_visible' : ''}
-                            mx_EmojiPicker_anchor_${category.id}`}
-                        onClick={() => this.props.onAnchorClick(category.id)} title={category.name} />
-                ))}
+            <nav className="mx_EmojiPicker_header" role="tablist" aria-label={_t("Categories")} onKeyDown={this.onKeyDown}>
+                {this.props.categories.map(category => {
+                    const classes = classNames(`mx_EmojiPicker_anchor mx_EmojiPicker_anchor_${category.id}`, {
+                        mx_EmojiPicker_anchor_visible: category.visible,
+                    });
+                    // Properties of this button are also modified by EmojiPicker's updateVisibility in DOM.
+                    return <button
+                        disabled={!category.enabled}
+                        key={category.id}
+                        ref={category.ref}
+                        className={classes}
+                        onClick={() => this.props.onAnchorClick(category.id)}
+                        title={category.name}
+                        role="tab"
+                        tabIndex={category.visible ? 0 : -1} // roving
+                        aria-selected={category.visible}
+                        aria-controls={`mx_EmojiPicker_category_${category.id}`}
+                    />;
+                })}
             </nav>
         );
     }

src/components/views/emojipicker/QuickReactions.js

@@ -72,7 +72,7 @@ class QuickReactions extends React.Component {
                         </React.Fragment>
                     }
                 </h2>
-                <ul className="mx_EmojiPicker_list">
+                <ul className="mx_EmojiPicker_list" aria-label={_t("Quick Reactions")}>
                     {QUICK_REACTIONS.map(emoji => <Emoji
                         key={emoji.hexcode} emoji={emoji} onClick={this.props.onClick}
                         onMouseEnter={this.onMouseEnter} onMouseLeave={this.onMouseLeave}

src/i18n/strings/en_EN.json

@@ -1408,6 +1408,7 @@
     "Objects": "Objects",
     "Symbols": "Symbols",
     "Flags": "Flags",
+    "Categories": "Categories",
     "Quick Reactions": "Quick Reactions",
     "Cancel search": "Cancel search",
     "Unknown Address": "Unknown Address",