Editor: Trigger reusable blocks autocomplete when options generated

packages/editor/src/components/autocompleters/block.js

@@ -1,7 +1,12 @@
+/**
+ * External dependencies
+ */
+import { once } from 'lodash';
+
 /**
  * WordPress dependencies
  */
-import { select } from '@wordpress/data';
+import { select, dispatch } from '@wordpress/data';
 import { createBlock } from '@wordpress/blocks';
 import { BlockIcon } from '@wordpress/block-editor';
 
@@ -41,6 +46,25 @@ function defaultGetSelectedBlockName() {
 	return selectedBlockClientId ? getBlockName( selectedBlockClientId ) : null;
 }
 
+/**
+ * Triggers a fetch of reusable blocks, once.
+ *
+ * TODO: Reusable blocks fetching should be reimplemented as a core-data entity
+ * resolver, not relying on `core/editor` (see #7119). The implementation here
+ * is imperfect in that the options result will not await the completion of the
+ * fetch request and thus will not include any reusable blocks. This has always
+ * been true, but relied upon the fact the user would be delayed in typing an
+ * autocompleter search query. Once implemented using resolvers, the status of
+ * this request could be subscribed to as part of a promised return value using
+ * the result of `hasFinishedResolution`. There is currently reliable way to
+ * determine that a reusable blocks fetch request has completed.
+ *
+ * @return {Promise} Promise resolving once reusable blocks fetched.
+ */
+const fetchReusableBlocks = once( () => {
+	dispatch( 'core/editor' ).__experimentalFetchReusableBlocks();
+} );
+
 /**
  * Creates a blocks repeater for replacing the current block with a selected block type.
  *
@@ -57,6 +81,8 @@ export function createBlockCompleter( {
 		className: 'editor-autocompleters__block',
 		triggerPrefix: '/',
 		options() {
+			fetchReusableBlocks();
+
 			const selectedBlockName = getSelectedBlockName();
 			return getInserterItems( getBlockInsertionParentClientId() ).filter(
 				// Avoid offering to replace the current block with a block of the same type.

packages/editor/src/components/autocompleters/test/block.js

@@ -7,9 +7,29 @@ import { shallow } from 'enzyme';
  * Internal dependencies
  */
 import blockCompleter, { createBlockCompleter } from '../block';
+import '../../../';
 
 describe( 'block', () => {
-	it( 'should retrieve block options for current insertion point', () => {
+	let originalFetch;
+	beforeEach( () => {
+		originalFetch = window.fetch;
+		window.fetch = ( url ) => {
+			if ( ! /\/wp\/v2\/types\/wp_block(\?|$)/.test( url ) ) {
+				throw new Error( 'Unhandled fetch ' + url );
+			}
+
+			return Promise.resolve( {
+				status: 200,
+				json: () => Promise.resolve( [] ),
+			} );
+		};
+	} );
+
+	afterEach( () => {
+		window.fetch = originalFetch;
+	} );
+
+	it( 'should retrieve block options for current insertion point', async () => {
 		const expectedOptions = [ {}, {}, {} ];
 		const mockGetBlockInsertionParentClientId = jest.fn( () => 'expected-insertion-point' );
 		const mockGetInserterItems = jest.fn( () => expectedOptions );

packages/editor/src/hooks/default-autocompleters.js

@@ -1,14 +1,13 @@
 /**
  * External dependencies
  */
-import { clone, once } from 'lodash';
+import { clone } from 'lodash';
 
 /**
  * WordPress dependencies
  */
 import { addFilter } from '@wordpress/hooks';
 import { getDefaultBlockName } from '@wordpress/blocks';
-import { dispatch } from '@wordpress/data';
 
 /**
  * Internal dependencies
@@ -17,23 +16,13 @@ import { blockAutocompleter, userAutocompleter } from '../components';
 
 const defaultAutocompleters = [ userAutocompleter ];
 
-const fetchReusableBlocks = once( () => dispatch( 'core/editor' ).__experimentalFetchReusableBlocks() );
-
 function setDefaultCompleters( completers, blockName ) {
 	if ( ! completers ) {
 		// Provide copies so filters may directly modify them.
 		completers = defaultAutocompleters.map( clone );
 		// Add blocks autocompleter for Paragraph block
 		if ( blockName === getDefaultBlockName() ) {
 			completers.push( clone( blockAutocompleter ) );
-
-			/*
-			 * NOTE: This is a hack to help ensure reusable blocks are loaded
-			 * so they may be included in the block completer. It can be removed
-			 * once we have a way for completers to Promise options while
-			 * store-based data dependencies are being resolved.
-			 */
-			fetchReusableBlocks();
 		}
 	}
 	return completers;