Editor: Optimize Inserter props generation and reconciliation

packages/editor/src/components/default-block-appender/test/__snapshots__/index.js.snap

@@ -23,7 +23,7 @@ exports[`DefaultBlockAppender should append a default block when input focused 1
     value="Write your story"
   />
   <WithSelect(WithDispatch(InserterWithShortcuts)) />
-  <WithSelect(WithDispatch(Inserter))
+  <WithSelect(IfCondition(Inserter))
     position="top right"
   />
 </div>
@@ -45,7 +45,7 @@ exports[`DefaultBlockAppender should match snapshot 1`] = `
     value="Write your story"
   />
   <WithSelect(WithDispatch(InserterWithShortcuts)) />
-  <WithSelect(WithDispatch(Inserter))
+  <WithSelect(IfCondition(Inserter))
     position="top right"
   />
 </div>
@@ -67,7 +67,7 @@ exports[`DefaultBlockAppender should optionally show without prompt 1`] = `
     value=""
   />
   <WithSelect(WithDispatch(InserterWithShortcuts)) />
-  <WithSelect(WithDispatch(Inserter))
+  <WithSelect(IfCondition(Inserter))
     position="top right"
   />
 </div>

packages/editor/src/components/inserter/index.js

@@ -3,10 +3,9 @@
  */
 import { __ } from '@wordpress/i18n';
 import { Dropdown, IconButton } from '@wordpress/components';
-import { createBlock, isUnmodifiedDefaultBlock } from '@wordpress/blocks';
 import { Component } from '@wordpress/element';
-import { withSelect, withDispatch } from '@wordpress/data';
-import { compose } from '@wordpress/compose';
+import { withSelect } from '@wordpress/data';
+import { compose, ifCondition } from '@wordpress/compose';
 
 /**
  * Internal dependencies
@@ -30,6 +29,8 @@ class Inserter extends Component {
 		super( ...arguments );
 
 		this.onToggle = this.onToggle.bind( this );
+		this.renderToggle = this.renderToggle.bind( this );
+		this.renderContent = this.renderContent.bind( this );
 	}
 
 	onToggle( isOpen ) {
@@ -41,20 +42,46 @@ class Inserter extends Component {
 		}
 	}
 
-	render() {
+	/**
+	 * Render callback to display Dropdown toggle element.
+	 *
+	 * @param {Function} options.onToggle Callback to invoke when toggle is
+	 *                                    pressed.
+	 * @param {boolean}  options.isOpen   Whether dropdown is currently open.
+	 *
+	 * @return {WPElement} Dropdown toggle element.
+	 */
+	renderToggle( { onToggle, isOpen } ) {
 		const {
-			items,
-			position,
-			title,
-			onInsertBlock,
-			rootClientId,
 			disabled,
 			renderToggle = defaultRenderToggle,
 		} = this.props;
 
-		if ( items.length === 0 ) {
-			return null;
-		}
+		return renderToggle( { onToggle, isOpen, disabled } );
+	}
+
+	/**
+	 * Render callback to display Dropdown content element.
+	 *
+	 * @param {Function} options.onClose Callback to invoke when dropdown is
+	 *                                   closed.
+	 *
+	 * @return {WPElement} Dropdown content element.
+	 */
+	renderContent( { onClose } ) {
+		const { rootClientId, index } = this.props;
+
+		return (
+			<InserterMenu
+				onSelect={ onClose }
+				rootClientId={ rootClientId }
+				index={ index }
+			/>
+		);
+	}
+
+	render() {
+		const { position, title } = this.props;
 
 		return (
 			<Dropdown
@@ -64,22 +91,8 @@ class Inserter extends Component {
 				onToggle={ this.onToggle }
 				expandOnMobile
 				headerTitle={ title }
-				renderToggle={ ( { onToggle, isOpen } ) => renderToggle( { onToggle, isOpen, disabled } ) }
-				renderContent={ ( { onClose } ) => {
-					const onSelect = ( item ) => {
-						onInsertBlock( item );
-
-						onClose();
-					};
-
-					return (
-						<InserterMenu
-							items={ items }
-							onSelect={ onSelect }
-							rootClientId={ rootClientId }
-						/>
-					);
-				} }
+				renderToggle={ this.renderToggle }
+				renderContent={ this.renderContent }
 			/>
 		);
 	}
@@ -90,7 +103,6 @@ export default compose( [
 		const {
 			getEditedPostAttribute,
 			getBlockInsertionPoint,
-			getSelectedBlock,
 			getInserterItems,
 		} = select( 'core/editor' );
 
@@ -106,21 +118,10 @@ export default compose( [
 
 		return {
 			title: getEditedPostAttribute( 'title' ),
-			selectedBlock: getSelectedBlock(),
-			items: getInserterItems( rootClientId ),
-			index,
+			hasItems: getInserterItems( rootClientId ).length > 0,
 			rootClientId,
+			index,
 		};
 	} ),
-	withDispatch( ( dispatch, ownProps ) => ( {
-		onInsertBlock: ( item ) => {
-			const { selectedBlock, index, rootClientId } = ownProps;
-			const { name, initialAttributes } = item;
-			const insertedBlock = createBlock( name, initialAttributes );
-			if ( selectedBlock && isUnmodifiedDefaultBlock( selectedBlock ) ) {
-				return dispatch( 'core/editor' ).replaceBlocks( selectedBlock.clientId, insertedBlock );
-			}
-			return dispatch( 'core/editor' ).insertBlock( insertedBlock, index, rootClientId );
-		},
-	} ) ),
+	ifCondition( ( { hasItems } ) => hasItems ),
 ] )( Inserter );

packages/editor/src/components/inserter/menu.js

@@ -23,7 +23,12 @@ import scrollIntoView from 'dom-scroll-into-view';
 import { __, _n, _x, sprintf } from '@wordpress/i18n';
 import { Component, findDOMNode, createRef } from '@wordpress/element';
 import { withSpokenMessages, PanelBody } from '@wordpress/components';
-import { getCategories, isReusableBlock } from '@wordpress/blocks';
+import {
+	getCategories,
+	isReusableBlock,
+	createBlock,
+	isUnmodifiedDefaultBlock,
+} from '@wordpress/blocks';
 import { withDispatch, withSelect } from '@wordpress/data';
 import { withInstanceId, compose, withSafeTimeout } from '@wordpress/compose';
 import { LEFT, RIGHT, UP, DOWN, BACKSPACE, ENTER } from '@wordpress/keycodes';
@@ -340,21 +345,55 @@ export class InserterMenu extends Component {
 export default compose(
 	withSelect( ( select, { rootClientId } ) => {
 		const {
-			getChildBlockNames,
-		} = select( 'core/blocks' );
-		const {
+			getEditedPostAttribute,
+			getSelectedBlock,
+			getInserterItems,
 			getBlockName,
 		} = select( 'core/editor' );
+		const {
+			getChildBlockNames,
+		} = select( 'core/blocks' );
+
 		const rootBlockName = getBlockName( rootClientId );
+
 		return {
+			selectedBlock: getSelectedBlock(),
 			rootChildBlocks: getChildBlockNames( rootBlockName ),
+			title: getEditedPostAttribute( 'title' ),
+			items: getInserterItems( rootClientId ),
+			rootClientId,
+		};
+	} ),
+	withDispatch( ( dispatch, ownProps ) => {
+		const {
+			__experimentalFetchReusableBlocks: fetchReusableBlocks,
+			showInsertionPoint,
+			hideInsertionPoint,
+		} = dispatch( 'core/editor' );
+
+		return {
+			fetchReusableBlocks,
+			showInsertionPoint,
+			hideInsertionPoint,
+			onSelect( item ) {
+				const {
+					replaceBlocks,
+					insertBlock,
+				} = dispatch( 'core/editor' );
+				const { selectedBlock, index, rootClientId } = ownProps;
+				const { name, initialAttributes } = item;
+
+				const insertedBlock = createBlock( name, initialAttributes );
+				if ( selectedBlock && isUnmodifiedDefaultBlock( selectedBlock ) ) {
+					replaceBlocks( selectedBlock.clientId, insertedBlock );
+				} else {
+					insertBlock( insertedBlock, index, rootClientId );
+				}
+
+				ownProps.onSelect();
+			},
 		};
 	} ),
-	withDispatch( ( dispatch ) => ( {
-		fetchReusableBlocks: dispatch( 'core/editor' ).__experimentalFetchReusableBlocks,
-		showInsertionPoint: dispatch( 'core/editor' ).showInsertionPoint,
-		hideInsertionPoint: dispatch( 'core/editor' ).hideInsertionPoint,
-	} ) ),
 	withSpokenMessages,
 	withInstanceId,
 	withSafeTimeout