Add keyboard navigation to the inserter.

editor/components/button/index.js

@@ -4,7 +4,7 @@
 import './style.scss';
 import classnames from 'classnames';
 
-function Button( { isPrimary, isLarge, isToggled, className, ...additionalProps } ) {
+function Button( { isPrimary, isLarge, isToggled, className, buttonRef, ...additionalProps } ) {
 	const classes = classnames( 'editor-button', className, {
 		button: ( isPrimary || isLarge ),
 		'button-primary': isPrimary,
@@ -16,6 +16,7 @@ function Button( { isPrimary, isLarge, isToggled, className, ...additionalProps
 		<button
 			type="button"
 			{ ...additionalProps }
+			ref={ buttonRef }
 			className={ classes } />
 	);
 }

editor/components/inserter/index.js

@@ -20,6 +20,10 @@ class Inserter extends wp.element.Component {
 	}
 
 	toggle() {
+		if ( this.state.opened ) {
+			this.toggleNode.focus();
+		}
+
 		this.setState( {
 			opened: ! this.state.opened
 		} );
@@ -51,8 +55,9 @@ class Inserter extends wp.element.Component {
 					onClick={ this.toggle }
 					className="editor-inserter__toggle"
 					aria-haspopup="true"
+					buttonRef={ ( node ) => this.toggleNode = node }
 					aria-expanded={ opened ? 'true' : 'false' } />
-				{ opened && <InserterMenu position={ position } onSelect={ this.close } /> }
+				{ opened && <InserterMenu position={ position } onSelect={ this.close } closeMenu={ this.toggle } /> }
 			</div>
 		);
 	}

editor/components/inserter/menu.js

@@ -2,6 +2,7 @@
  * External dependencies
  */
 import { connect } from 'react-redux';
+import { flow } from 'lodash';
 
 /**
  * Internal dependencies
@@ -12,11 +13,58 @@ import Dashicon from 'components/dashicon';
 class InserterMenu extends wp.element.Component {
 	constructor() {
 		super( ...arguments );
+		this.blockTypes = wp.blocks.getBlocks();
+		this.categories = wp.blocks.getCategories();
+		this.nodes = {};
 		this.state = {
-			filterValue: ''
+			filterValue: '',
+			currentFocus: null
 		};
 		this.filter = this.filter.bind( this );
 		this.instanceId = this.constructor.instances++;
+		this.isShownBlock = this.isShownBlock.bind( this );
+		this.setSearchFocus = this.setSearchFocus.bind( this );
+		this.onKeyDown = this.onKeyDown.bind( this );
+		this.getVisibleBlocks = this.getVisibleBlocks.bind( this );
+		this.sortBlocksByCategory = this.sortBlocksByCategory.bind( this );
+	}
+
+	componentDidMount() {
+		document.addEventListener( 'keydown', this.onKeyDown );
+	}
+
+	componentWillUnmount() {
+		document.removeEventListener( 'keydown', this.onKeyDown );
+	}
+
+	isShownBlock( block ) {
+		return block.title.toLowerCase().indexOf( this.state.filterValue.toLowerCase() ) !== -1;
+	}
+
+	bindReferenceNode( nodeName ) {
+		return ( node ) => this.nodes[ nodeName ] = node;
+	}
+
+	isNextKeydown( keydown ) {
+		return keydown.code === 'ArrowDown'
+			|| ( keydown.code === 'Tab' && keydown.shiftKey === false );
+	}
+
+	isArrowRight( keydown ) {
+		return keydown.code === 'ArrowRight';
+	}
+
+	isArrowLeft( keydown ) {
+		return keydown.code === 'ArrowLeft';
+	}
+
+	isPreviousKeydown( keydown ) {
+		return keydown.code === 'ArrowUp'
+			|| ( keydown.code === 'Tab' && keydown.shiftKey === true );
+	}
+
+	isEscapeKey( keydown ) {
+		return keydown.code === 'Escape';
 	}
 
 	filter( event ) {
@@ -29,32 +77,206 @@ class InserterMenu extends wp.element.Component {
 		return () => {
 			this.props.onInsertBlock( slug );
 			this.props.onSelect();
-			this.setState( { filterValue: '' } );
+			this.setState( {
+				filterValue: '',
+				currentFocus: null
+			} );
 		};
 	}
 
-	render() {
-		const { position = 'top' } = this.props;
-		const blocks = wp.blocks.getBlocks();
-		const isShownBlock = block => block.title.toLowerCase().indexOf( this.state.filterValue.toLowerCase() ) !== -1;
-		const blocksByCategory = blocks.reduce( ( groups, block ) => {
-			if ( ! isShownBlock( block ) ) {
-				return groups;
-			}
-			if ( ! groups[ block.category ] ) {
-				groups[ block.category ] = [];
+	getVisibleBlocks( blockTypes ) {
+		return blockTypes.filter( this.isShownBlock );
+	}
+
+	sortBlocksByCategory( blockTypes ) {
+		const getCategoryIndex = ( item ) => {
+			return this.categories.findIndex( ( category ) => category.slug === item.slug );
+		};
+
+		return blockTypes.sort( ( a, b ) => {
+			return getCategoryIndex( a ) - getCategoryIndex( b );
+		} );
+	}
+
+	groupByCategory( blockTypes ) {
+		return blockTypes.reduce( ( accumulator, block ) => {
+			// If already an array push block on else add array of block.
+			if ( Array.isArray( accumulator[ block.category ] ) ) {
+				accumulator[ block.category ].push( block );
+				return accumulator;
 			}
-			groups[ block.category ].push( block );
-			return groups;
+
+			accumulator[ block.category ] = [ block ];
+			return accumulator;
 		}, {} );
-		const categories = wp.blocks.getCategories();
+	}
+
+	getVisibleBlocksByCategory( blockTypes ) {
+		return flow(
+			this.getVisibleBlocks,
+			this.sortBlocksByCategory,
+			this.groupByCategory
+		)( blockTypes );
+	}
+
+	findNext( currentBlock, blockTypes ) {
+		/**
+		 * null is the value that will trigger iterating back to
+		 * the top of the list of block types.
+		 */
+		if ( null === currentBlock ) {
+			return blockTypes[ 0 ].slug;
+		}
+
+		const currentIndex = blockTypes.findIndex( ( blockType ) => currentBlock === blockType.slug );
+		const nextIndex = currentIndex + 1;
+		const highestIndex = blockTypes.length - 1;
+
+		/**
+		 * Default currently for going past the blocks is search, may need to be
+		 * revised in the future as more focusable elements are added. This
+		 * returns a null value, which currently implies that search will be set
+		 * as the next focus.
+		 */
+		if ( nextIndex > highestIndex ) {
+			return null;
+		}
+
+		// Return the slug of the next block type.
+		return blockTypes[ nextIndex ].slug;
+	}
+
+	findPrevious( currentBlock, blockTypes ) {
+		/**
+		 * null will trigger iterating back to the top of the list of block
+		 * types.
+		 */
+		if ( null === currentBlock ) {
+			return blockTypes[ 0 ].slug;
+		}
+
+		const highestIndex = blockTypes.length - 1;
+
+		// If the search bar is focused navigate to the bottom of the block list.
+		if ( 'search' === currentBlock ) {
+			return blockTypes[ highestIndex ].slug;
+		}
+
+		const currentIndex = blockTypes.findIndex( ( blockType ) => currentBlock === blockType.slug );
+		const previousIndex = currentIndex - 1;
+		const lowestIndex = 0;
+
+		/**
+		 * Default currently for going past the blocks is search, may need to be
+		 * revised in the future as more focusable elements are added. This
+		 * returns a null value, which currently implies that search will be set
+		 * as the next focus.
+		 */
+		if ( previousIndex < lowestIndex ) {
+			return null;
+		}
+
+		// Return the slug of the next block type.
+		return blockTypes[ previousIndex ].slug;
+	}
+
+	focusNext( component ) {
+		const sortedByCategory = flow(
+			this.getVisibleBlocks,
+			this.sortBlocksByCategory,
+		)( component.blockTypes );
+
+		// If the block list is empty return early.
+		if ( ! sortedByCategory.length ) {
+			return;
+		}
+
+		const currentBlock = component.state.currentFocus;
+
+		const nextBlock = this.findNext( currentBlock, sortedByCategory );
+		this.changeMenuSelection( nextBlock );
+	}
+
+	focusPrevious( component ) {
+		const sortedByCategory = flow(
+			this.getVisibleBlocks,
+			this.sortBlocksByCategory,
+		)( component.blockTypes );
+		const currentBlock = component.state.currentFocus;
+
+		// If the block list is empty return early.
+		if ( ! sortedByCategory.length ) {
+			return;
+		}
+
+		const nextBlock = this.findPrevious( currentBlock, sortedByCategory );
+		this.changeMenuSelection( nextBlock );
+	}
+
+	onKeyDown( keydown ) {
+		if ( this.isNextKeydown( keydown ) ) {
+			keydown.preventDefault();
+			this.focusNext( this );
+		}
+
+		if ( this.isPreviousKeydown( keydown ) ) {
+			keydown.preventDefault();
+			this.focusPrevious( this );
+		}
+
+		/**
+		 * Left and right arrow keys need to be handled seperately so that
+		 * default cursor behavior can be handled in the search field.
+		 */
+		if ( this.isArrowRight( keydown ) ) {
+			if ( this.state.currentFocus === 'search' ) {
+				return;
+			}
+			this.focusNext( this );
+		}
+
+		if ( this.isArrowLeft( keydown ) ) {
+			if ( this.state.currentFocus === 'search' ) {
+				return;
+			}
+			this.focusPrevious( this );
+		}
+
+		if ( this.isEscapeKey( keydown ) ) {
+			keydown.preventDefault();
+			this.props.closeMenu();
+		}
+	}
+
+	changeMenuSelection( refName ) {
+		if ( refName === null ) {
+			refName = 'search';
+		}
+
+		this.setState( {
+			currentFocus: refName
+		} );
+
+		// Focus the DOM node.
+		this.nodes[ refName ].focus();
+	}
+
+	setSearchFocus() {
+		this.changeMenuSelection( 'search' );
+	}
+
+	render() {
+		const { position = 'top' } = this.props;
+		const blocks = this.blockTypes;
+		const visibleBlocksByCategory = this.getVisibleBlocksByCategory( blocks );
+		const categories = this.categories;
 
 		return (
-			<div className={ `editor-inserter__menu is-${ position }` }>
+			<div className={ `editor-inserter__menu is-${ position }` } tabIndex="0">
 				<div className="editor-inserter__arrow" />
-				<div className="editor-inserter__content">
+				<div role="menu" className="editor-inserter__content">
 					{ categories
-						.map( ( category ) => !! blocksByCategory[ category.slug ] && (
+						.map( ( category ) => !! visibleBlocksByCategory[ category.slug ] && (
 							<div key={ category.slug }>
 								<div
 									className="editor-inserter__separator"
@@ -69,12 +291,14 @@ class InserterMenu extends wp.element.Component {
 									tabIndex="0"
 									aria-labelledby={ `editor-inserter__separator-${ category.slug }-${ this.instanceId }` }
 								>
-									{ blocksByCategory[ category.slug ].map( ( { slug, title, icon } ) => (
+									{ visibleBlocksByCategory[ category.slug ].map( ( { slug, title, icon } ) => (
 										<button
 											role="menuitem"
 											key={ slug }
 											className="editor-inserter__block"
 											onClick={ this.selectBlock( slug ) }
+											ref={ this.bindReferenceNode( slug ) }
+											tabIndex="-1"
 										>
 											<Dashicon icon={ icon } />
 											{ title }
@@ -94,6 +318,9 @@ class InserterMenu extends wp.element.Component {
 					placeholder={ wp.i18n.__( 'Search…' ) }
 					className="editor-inserter__search"
 					onChange={ this.filter }
+					onClick={ this.setSearchFocus }
+					ref={ this.bindReferenceNode( 'search' ) }
+					tabIndex="-1"
 				/>
 			</div>
 		);

editor/components/inserter/style.scss

@@ -21,7 +21,8 @@
 	outline: none;
 	transition: color .2s ease;
 
-	&:hover {
+	&:hover,
+	&:focus {
 		color: $blue-medium;
 	}
 }
@@ -145,6 +146,7 @@ input[type=search].editor-inserter__search {
 	&:focus {
 		border: 1px solid $dark-gray-500;
 		outline: none;
+		position: relative;
 	}
 
 	&:active,