Emoji Picker Menu Navigation

src/CONST.js

@@ -114,6 +114,9 @@ const CONST = {
     },
 
     EMOJI_PICKER_SIZE: 360,
+    NON_NATIVE_EMOJI_PICKER_LIST_HEIGHT: 300,
+    EMOJI_PICKER_ITEM_HEIGHT: 40,
+    EMOJI_PICKER_HEADER_HEIGHT: 38,
 
     EMAIL: {
         CHRONOS: 'chronos@expensify.com',

src/pages/home/report/EmojiPickerMenu/index.js

@@ -31,6 +31,9 @@ class EmojiPickerMenu extends Component {
         // Ref for the emoji search input
         this.searchInput = undefined;
 
+        // Ref for emoji FlatList
+        this.emojiList = undefined;
+
         // This is the number of columns in each row of the picker.
         // Because of how flatList implements these rows, each row is an index rather than each element
         // For this reason to make headers work, we need to have the header be the only rendered element in its row
@@ -45,11 +48,19 @@ class EmojiPickerMenu extends Component {
         this.unfilteredHeaderIndices = [0, 33, 59, 87, 98, 120, 147];
 
         this.filterEmojis = _.debounce(this.filterEmojis.bind(this), 300);
+        this.highlightAdjacentEmoji = this.highlightAdjacentEmoji.bind(this);
+        this.scrollToHighlightedIndex = this.scrollToHighlightedIndex.bind(this);
+        this.toggleArrowKeysOnSearchInput = this.toggleArrowKeysOnSearchInput.bind(this);
+        this.setupEventHandlers = this.setupEventHandlers.bind(this);
+        this.cleanupEventHandlers = this.cleanupEventHandlers.bind(this);
         this.renderItem = this.renderItem.bind(this);
 
         this.state = {
             filteredEmojis: emojis,
             headerIndices: this.unfilteredHeaderIndices,
+            highlightedIndex: -1,
+            currentScrollOffset: 0,
+            arePointerEventsDisabled: false,
         };
     }
 
@@ -61,6 +72,146 @@ class EmojiPickerMenu extends Component {
         if (this.props.forwardedRef && _.isFunction(this.props.forwardedRef)) {
             this.props.forwardedRef(this.searchInput);
         }
+        this.setupEventHandlers();
+    }
+
+    componentWillUnmount() {
+        this.cleanupEventHandlers();
+    }
+
+    /**
+     * Setup and attach keypress/mouse handlers for highlight navigation.
+     */
+    setupEventHandlers() {
+        if (document) {
+            this.keyDownHandler = (keyBoardEvent) => {
+                if (keyBoardEvent.key.startsWith('Arrow')) {
+                    // Depending on the position of the highlighted emoji after moving and rendering,
+                    // toggle which arrow keys can affect the cursor position in the search input.
+                    this.toggleArrowKeysOnSearchInput(keyBoardEvent);
+
+                    // Move the highlight when arrow keys are pressed
+                    this.highlightAdjacentEmoji(keyBoardEvent.key);
+                }
+
+                // Select the currently highlighted emoji if enter is pressed
+                if (keyBoardEvent.key === 'Enter' && this.state.highlightedIndex !== -1) {
+                    this.props.onEmojiSelected(this.state.filteredEmojis[this.state.highlightedIndex].code);
+                }
+            };
+            document.addEventListener('keydown', this.keyDownHandler);
+
+            // Re-enable pointer events and hovering over EmojiPickerItems when the mouse moves
+            this.mouseMoveHandler = () => {
+                if (this.state.arePointerEventsDisabled) {
+                    this.setState({arePointerEventsDisabled: false});
+                }
+            };
+            document.addEventListener('mousemove', this.mouseMoveHandler);
+        }
+    }
+
+    /**
+     * Cleanup all mouse/keydown event listeners that we've set up
+     */
+    cleanupEventHandlers() {
+        if (document) {
+            document.removeEventListener('keydown', this.keyDownHandler);
+            document.removeEventListener('mousemove', this.mouseMoveHandler);
+        }
+    }
+
+    /**
+     * Highlights emojis adjacent to the currently highlighted emoji depending on the arrowKey
+     * @param {String} arrowKey
+     */
+    highlightAdjacentEmoji(arrowKey) {
+        const firstNonHeaderIndex = this.state.filteredEmojis.length === emojis.length ? this.numColumns : 0;
+
+        // If nothing is highlighted and an arrow key is pressed
+        // select the first emoji
+        if (this.state.highlightedIndex === -1) {
+            this.setState({highlightedIndex: firstNonHeaderIndex});
+            this.scrollToHighlightedIndex();
+            return;
+        }
+
+        let newIndex = this.state.highlightedIndex;
+        const move = (steps, boundsCheck) => {
+            if (boundsCheck()) {
+                return;
+            }
+
+            // Move in the prescribed direction until we reach an element that isn't a header
+            const isHeader = e => e.header || e.code === CONST.EMOJI_SPACER;
+            do {
+                newIndex += steps;
+            } while (isHeader(this.state.filteredEmojis[newIndex]));
+        };
+
+        switch (arrowKey) {
+            case 'ArrowDown':
+                move(
+                    this.numColumns,
+                    () => this.state.highlightedIndex + this.numColumns > this.state.filteredEmojis.length - 1,
+                );
+                break;
+            case 'ArrowLeft':
+                move(-1, () => this.state.highlightedIndex - 1 < firstNonHeaderIndex);
+                break;
+            case 'ArrowRight':
+                move(1, () => this.state.highlightedIndex + 1 > this.state.filteredEmojis.length - 1);
+                break;
+            case 'ArrowUp':
+                move(-this.numColumns, () => this.state.highlightedIndex - this.numColumns < firstNonHeaderIndex);
+                break;
+            default:
+                break;
+        }
+
+        // Actually highlight the new emoji and scroll to it if the index was changed
+        if (newIndex !== this.state.highlightedIndex) {
+            this.setState({highlightedIndex: newIndex});
+            this.scrollToHighlightedIndex();
+        }
+    }
+
+    /**
+     * Calculates the required scroll offset (aka distance from top) and scrolls the FlatList to the highlighted emoji
+     * if any portion of it falls outside of the window.
+     * Doing this because scrollToIndex doesn't work as expected.
+     */
+    scrollToHighlightedIndex() {
+        // If there are headers in the emoji array, so we need to offset by their heights as well
+        let numHeaders = 0;
+        if (this.state.filteredEmojis.length === emojis.length) {
+            numHeaders = this.unfilteredHeaderIndices
+                .filter(i => this.state.highlightedIndex > i * this.numColumns).length;
+        }
+
+        // Calculate the scroll offset at the bottom of the currently highlighted emoji
+        // (subtract numHeaders because the highlightedIndex includes them, and add 1 to include the current row)
+        const numEmojiRows = (Math.floor(this.state.highlightedIndex / this.numColumns) - numHeaders) + 1;
+
+        // The scroll offsets at the top and bottom of the highlighted emoji
+        const offsetAtEmojiBottom = ((numHeaders) * CONST.EMOJI_PICKER_HEADER_HEIGHT)
+            + (numEmojiRows * CONST.EMOJI_PICKER_ITEM_HEIGHT);
+        const offsetAtEmojiTop = offsetAtEmojiBottom - CONST.EMOJI_PICKER_ITEM_HEIGHT;
+
+        // Scroll to fit the entire highlighted emoji into the window if we need to
+        let targetOffset = this.state.currentScrollOffset;
+        if (offsetAtEmojiBottom - this.state.currentScrollOffset >= CONST.NON_NATIVE_EMOJI_PICKER_LIST_HEIGHT) {
+            targetOffset = offsetAtEmojiBottom - CONST.NON_NATIVE_EMOJI_PICKER_LIST_HEIGHT;
+        } else if (offsetAtEmojiTop - CONST.EMOJI_PICKER_ITEM_HEIGHT <= this.state.currentScrollOffset) {
+            targetOffset = offsetAtEmojiTop - CONST.EMOJI_PICKER_ITEM_HEIGHT;
+        }
+        if (targetOffset !== this.state.currentScrollOffset) {
+            // Disable pointer events so that onHover doesn't get triggered when the items move while we're scrolling
+            if (!this.state.arePointerEventsDisabled) {
+                this.setState({arePointerEventsDisabled: true});
+            }
+            this.emojiList.scrollToOffset({offset: targetOffset, animated: false});
+        }
     }
 
     /**
@@ -72,7 +223,11 @@ class EmojiPickerMenu extends Component {
         const normalizedSearchTerm = searchTerm.toLowerCase();
         if (normalizedSearchTerm === '') {
             // There are no headers when searching, so we need to re-make them sticky when there is no search term
-            this.setState({filteredEmojis: emojis, headerIndices: this.unfilteredHeaderIndices});
+            this.setState({
+                filteredEmojis: emojis,
+                headerIndices: this.unfilteredHeaderIndices,
+                highlightedIndex: this.numColumns,
+            });
             return;
         }
 
@@ -83,7 +238,28 @@ class EmojiPickerMenu extends Component {
         ));
 
         // Remove sticky header indices. There are no headers while searching and we don't want to make emojis sticky
-        this.setState({filteredEmojis: newFilteredEmojiList, headerIndices: []});
+        this.setState({filteredEmojis: newFilteredEmojiList, headerIndices: [], highlightedIndex: 0});
+    }
+
+    /**
+     * Toggles which arrow keys can affect the cursor in the search input,
+     * depending on whether the arrow keys will affect the index of the highlighted emoji.
+     *
+     * @param {KeyboardEvent} arrowKeyBoardEvent
+     */
+    toggleArrowKeysOnSearchInput(arrowKeyBoardEvent) {
+        let keysToIgnore = ['ArrowDown', 'ArrowRight', 'ArrowLeft', 'ArrowUp'];
+        if (this.state.highlightedIndex === 0 && this.state.filteredEmojis.length) {
+            keysToIgnore = ['ArrowDown', 'ArrowRight'];
+        } else if (this.state.highlightedIndex === this.state.filteredEmojis.length - 1) {
+            keysToIgnore = ['ArrowLeft', 'ArrowUp'];
+        }
+
+        // Moving the cursor is the default behavior for arrow key presses while an input is focused,
+        // so prevent it
+        if (keysToIgnore.includes(arrowKeyBoardEvent.key)) {
+            arrowKeyBoardEvent.preventDefault();
+        }
     }
 
     /**
@@ -92,32 +268,39 @@ class EmojiPickerMenu extends Component {
      * so that the sticky headers function properly
      *
      * @param {Object} item
+     * @param {Number} index
      * @returns {*}
      */
-    renderItem({item}) {
-        if (item.code === CONST.EMOJI_SPACER) {
+    renderItem({item, index}) {
+        const {code, header} = item;
+        if (code === CONST.EMOJI_SPACER) {
             return null;
         }
 
-        if (item.header) {
+        if (header) {
             return (
                 <Text style={styles.emojiHeaderStyle}>
-                    {item.code}
+                    {code}
                 </Text>
             );
         }
 
         return (
             <EmojiPickerMenuItem
                 onPress={this.props.onEmojiSelected}
-                emoji={item.code}
+                onHover={() => this.setState({highlightedIndex: index})}
+                emoji={code}
+                isHighlighted={index === this.state.highlightedIndex}
             />
         );
     }
 
     render() {
         return (
-            <View style={styles.emojiPickerContainer}>
+            <View
+                style={styles.emojiPickerContainer}
+                pointerEvents={this.state.arePointerEventsDisabled ? 'none' : 'auto'}
+            >
                 {!this.props.isSmallScreenWidth && (
                     <View style={[styles.pt4, styles.ph4, styles.pb1]}>
                         <TextInputFocusable
@@ -132,13 +315,15 @@ class EmojiPickerMenu extends Component {
                     </View>
                 )}
                 <FlatList
+                    ref={el => this.emojiList = el}
                     data={this.state.filteredEmojis}
                     renderItem={this.renderItem}
                     keyExtractor={item => `emoji_picker_${item.code}`}
                     numColumns={this.numColumns}
                     style={styles.emojiPickerList}
-                    extraData={this.state.filteredEmojis}
+                    extraData={[this.state.filteredEmojis, this.state.highlightedIndex]}
                     stickyHeaderIndices={this.state.headerIndices}
+                    onScroll={e => this.setState({currentScrollOffset: e.nativeEvent.contentOffset.y})}
                 />
             </View>
         );

src/pages/home/report/EmojiPickerMenuItem.js

@@ -3,28 +3,46 @@ import PropTypes from 'prop-types';
 import {Pressable, Text} from 'react-native';
 import styles, {getButtonBackgroundColorStyle} from '../../../styles/styles';
 import getButtonState from '../../../libs/getButtonState';
+import Hoverable from '../../../components/Hoverable';
 
 const propTypes = {
     // The unicode that is used to display the emoji
     emoji: PropTypes.string.isRequired,
 
     // The function to call when an emoji is selected
     onPress: PropTypes.func.isRequired,
+
+    // Handles what to do when we hover over this item with our cursor
+    onHover: PropTypes.func.isRequired,
+
+    // Whether this menu item is currently highlighted or not
+    isHighlighted: PropTypes.bool.isRequired,
 };
 
 const EmojiPickerMenuItem = props => (
     <Pressable
         onPress={() => props.onPress(props.emoji)}
-        style={({hovered, pressed}) => ([
+        style={({
+            pressed,
+        }) => ([
             styles.emojiItem,
-            getButtonBackgroundColorStyle(getButtonState(hovered, pressed)),
+            getButtonBackgroundColorStyle(getButtonState(false, pressed)),
+            props.isHighlighted ? styles.emojiItemHighlighted : {},
         ])}
     >
-        <Text style={styles.emojiText}>{props.emoji}</Text>
+        <Hoverable onHoverIn={props.onHover}>
+            <Text style={styles.emojiText}>{props.emoji}</Text>
+        </Hoverable>
     </Pressable>
+
 );
 
 EmojiPickerMenuItem.propTypes = propTypes;
 EmojiPickerMenuItem.displayName = 'EmojiPickerMenuItem';
 
-export default EmojiPickerMenuItem;
+// Significantly speeds up re-renders of the EmojiPickerMenu's FlatList
+// by only re-rendering at most two EmojiPickerMenuItems that are highlighted/un-highlighted per user action.
+export default React.memo(
+    EmojiPickerMenuItem,
+    (prevProps, nextProps) => prevProps.isHighlighted === nextProps.isHighlighted,
+);

src/styles/styles.js

@@ -853,7 +853,14 @@ const styles = {
 
     emojiItem: {
         width: '12.5%',
+        height: 40,
         textAlign: 'center',
+        borderRadius: 8,
+    },
+
+    emojiItemHighlighted: {
+        transition: '0.2s ease',
+        backgroundColor: themeColors.buttonDefaultBG,
     },
 
     chatItemEmojiButton: {