From eaee07522e493fdbc7725df7c6f2aa2d3a38b475 Mon Sep 17 00:00:00 2001
From: Nik Tsekouras <ntsekouras@outlook.com>
Date: Wed, 17 Feb 2021 08:46:12 +0200
Subject: [PATCH] Prioritize core blocks in the inserter (#28945)

* prioritze core blocks in the inserter context

* prioritize core blocks in the selector
---
 .../components/inserter/block-types-tab.js    | 12 +---
 packages/block-editor/src/store/selectors.js  | 22 +++++--
 .../block-editor/src/store/test/selectors.js  | 64 +++++++++++++++++++
 3 files changed, 84 insertions(+), 14 deletions(-)

diff --git a/packages/block-editor/src/components/inserter/block-types-tab.js b/packages/block-editor/src/components/inserter/block-types-tab.js
index 94b76b02ac694f..00b51a4ed2165d 100644
--- a/packages/block-editor/src/components/inserter/block-types-tab.js
+++ b/packages/block-editor/src/components/inserter/block-types-tab.js
@@ -1,7 +1,7 @@
 /**
  * External dependencies
  */
-import { map, findIndex, flow, sortBy, groupBy, orderBy } from 'lodash';
+import { map, flow, groupBy, orderBy } from 'lodash';
 
 /**
  * WordPress dependencies
@@ -43,22 +43,14 @@ export function BlockTypesTab( {
 	}, [ items ] );
 
 	const itemsPerCategory = useMemo( () => {
-		const getCategoryIndex = ( item ) => {
-			return findIndex(
-				categories,
-				( category ) => category.slug === item.category
-			);
-		};
-
 		return flow(
 			( itemList ) =>
 				itemList.filter(
 					( item ) => item.category && item.category !== 'reusable'
 				),
-			( itemList ) => sortBy( itemList, getCategoryIndex ),
 			( itemList ) => groupBy( itemList, 'category' )
 		)( items );
-	}, [ items, categories ] );
+	}, [ items ] );
 
 	const itemsPerCollection = useMemo( () => {
 		// Create a new Object to avoid mutating collection.
diff --git a/packages/block-editor/src/store/selectors.js b/packages/block-editor/src/store/selectors.js
index ae383dff603312..8dcac3f9cfb8c4 100644
--- a/packages/block-editor/src/store/selectors.js
+++ b/packages/block-editor/src/store/selectors.js
@@ -1600,12 +1600,26 @@ export const getInserterItems = createSelector(
 				blockVariations.push( ...variations.map( variationMapper ) );
 			}
 		}
-
-		return [
+		// Prioritize core blocks's display in inserter.
+		const prioritizeCoreBlocks = ( a, b ) => {
+			const coreBlockNamePrefix = 'core/';
+			const firstIsCoreBlock = a.name.startsWith( coreBlockNamePrefix );
+			const secondIsCoreBlock = b.name.startsWith( coreBlockNamePrefix );
+			if ( firstIsCoreBlock && secondIsCoreBlock ) {
+				return 0;
+			}
+			return firstIsCoreBlock && ! secondIsCoreBlock ? -1 : 1;
+		};
+		// Ensure core blocks are prioritized in the returned results,
+		// because third party blocks can be registered earlier than
+		// the core blocks (usually by using the `init` action),
+		// thus affecting the display order.
+		// We don't sort reusable blocks as they are handled differently.
+		const sortedBlockTypes = [
 			...visibleBlockTypeInserterItems,
 			...blockVariations,
-			...reusableBlockInserterItems,
-		];
+		].sort( prioritizeCoreBlocks );
+		return [ ...sortedBlockTypes, ...reusableBlockInserterItems ];
 	},
 	( state, rootClientId ) => [
 		state.blockListSettings[ rootClientId ],
diff --git a/packages/block-editor/src/store/test/selectors.js b/packages/block-editor/src/store/test/selectors.js
index 77f6ba4df1987e..6ea84f777df21e 100644
--- a/packages/block-editor/src/store/test/selectors.js
+++ b/packages/block-editor/src/store/test/selectors.js
@@ -3423,3 +3423,67 @@ describe( '__experimentalGetParsedReusableBlock', () => {
 		);
 	} );
 } );
+
+describe( 'getInserterItems with core blocks prioritization', () => {
+	// This test is in a seperate `describe` because all other tests register
+	// some test `core` blocks and interfere with the purpose of the specific test.
+	// This tests the functionality to ensure core blocks are prioritized in the
+	// returned results, because third party blocks can be registered earlier than
+	// the core blocks (usually by using the `init` action), thus affecting the display order.
+	beforeEach( () => {
+		registerBlockType( 'plugin/block-a', {
+			save() {},
+			category: 'text',
+			title: 'Plugin Block A',
+			icon: 'test',
+		} );
+		registerBlockType( 'another-plugin/block-b', {
+			save() {},
+			category: 'text',
+			title: 'Another Plugin Block B',
+			icon: 'test',
+		} );
+		registerBlockType( 'core/block', {
+			save() {},
+			category: 'text',
+			title: 'Core Block A',
+		} );
+		registerBlockType( 'core/test-block-a', {
+			save: ( props ) => props.attributes.text,
+			category: 'design',
+			title: 'Core Block B',
+			icon: 'test',
+			keywords: [ 'testing' ],
+		} );
+	} );
+	afterEach( () => {
+		[
+			'plugin/block-a',
+			'another-plugin/block-b',
+			'core/block',
+			'core/test-block-a',
+		].forEach( unregisterBlockType );
+	} );
+	it( 'should prioritize core blocks by sorting them at the top of the returned list', () => {
+		const state = {
+			blocks: {
+				byClientId: {},
+				attributes: {},
+				order: {},
+				parents: {},
+				cache: {},
+			},
+			settings: {},
+			preferences: {},
+			blockListSettings: {},
+		};
+		const items = getInserterItems( state );
+		const expectedResult = [
+			'core/block',
+			'core/test-block-a',
+			'plugin/block-a',
+			'another-plugin/block-b',
+		];
+		expect( items.map( ( { name } ) => name ) ).toEqual( expectedResult );
+	} );
+} );