Allow passing optional afterLoad callbacks to store calls

packages/e2e-tests/plugins/interactive-blocks/store-afterload/block.json

@@ -0,0 +1,14 @@
+{
+	"apiVersion": 2,
+	"name": "test/store-afterload",
+	"title": "E2E Interactivity tests - store afterload",
+	"category": "text",
+	"icon": "heart",
+	"description": "",
+	"supports": {
+		"interactivity": true
+	},
+	"textdomain": "e2e-interactivity",
+	"viewScript": "store-afterload-view",
+	"render": "file:./render.php"
+}

packages/e2e-tests/plugins/interactive-blocks/store-afterload/render.php

@@ -0,0 +1,41 @@
+<?php
+/**
+ * HTML for testing `afterLoad` callbacks added to the store.
+ *
+ * @package gutenberg-test-interactive-blocks
+ */
+
+?>
+<div data-wp-interactive>
+	<h3>Store statuses</h3>
+	<p data-store-status data-wp-text="state.status1">waiting</p>
+	<p data-store-status data-wp-text="state.status2">waiting</p>
+	<p data-store-status data-wp-text="state.status3">waiting</p>
+	<p data-store-status data-wp-text="state.status4">waiting</p>
+
+	<h3><code>afterLoad</code> executions</h3>
+	<p>All stores ready:&#20;
+		<span
+			data-testid="all-stores-ready"
+			data-wp-text="state.allStoresReady">
+		>waiting</span>
+	</p>
+	<p>vDOM ready:&#20;
+		<span
+			data-testid="vdom-ready"
+			data-wp-text="state.vdomReady">
+		>waiting</span>
+	</p>
+	<p><code>afterLoad</code> exec times:&#20;
+		<span
+			data-testid="after-load-exec-times"
+			data-wp-text="state.execTimes.afterLoad">
+		>0</span>
+	</p>
+	<p><code>sharedAfterLoad</code> exec times:&#20;
+		<span
+			data-testid="shared-after-load-exec-times"
+			data-wp-text="state.execTimes.sharedAfterLoad">
+		>0</span>
+	</p>
+</div>

packages/e2e-tests/plugins/interactive-blocks/store-afterload/view.js

@@ -0,0 +1,60 @@
+( ( { wp } ) => {
+	/**
+	 * WordPress dependencies
+	 */
+	const { store } = wp.interactivity;
+
+	const afterLoad = ({ state }) => {
+		// Check the state is correctly initialized.
+		const { status1, status2, status3, status4 } = state;
+		state.allStoresReady =
+			[ status1, status2, status3, status4 ]
+				.every( ( t ) => t === 'ready' )
+				.toString();
+
+		// Check the HTML has been processed as well.
+		const selector = '[data-store-status]';
+		state.vdomReady =
+			document.querySelector( selector ) &&
+				Array.from(
+					document.querySelectorAll( selector )
+				).every( ( el ) => el.textContent === 'ready' ).toString();
+
+		// Increment exec times everytime this function runs.
+		state.execTimes.afterLoad += 1;
+	}
+
+	const sharedAfterLoad = ({ state }) => {
+		// Increment exec times everytime this function runs.
+		state.execTimes.sharedAfterLoad += 1;
+	}
+
+	// Case 1: without afterload callback
+	store( {
+		state: { status1: 'ready' },
+	} );
+
+	// Case 2: non-shared afterload callback
+	store( {
+		state: {
+			status2: 'ready',
+			allStoresReady: false,
+			vdomReady: false,
+			execTimes: { afterLoad: 0 },
+		},
+	}, { afterLoad } );
+
+	// Case 3: shared afterload callback
+	store( {
+		state: {
+			status3: 'ready',
+			execTimes: { sharedAfterLoad: 0 },
+		},
+	}, { afterLoad: sharedAfterLoad }  );
+	store( {
+		state: {
+			status4: 'ready',
+			execTimes: { sharedAfterLoad: 0 },
+		},
+	}, { afterLoad: sharedAfterLoad }  );
+} )( window );

packages/interactivity/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### New Features
+
+-   Allow passing optional `afterLoad` callbacks to `store` calls. ([#53363](https://github.com/WordPress/gutenberg/pull/53363))
+
 ### Bug Fix
 
 -   Add support for underscores and leading dashes in the suffix part of the directive. ([#53337](https://github.com/WordPress/gutenberg/pull/53337))

packages/interactivity/src/index.js

@@ -3,6 +3,7 @@
  */
 import registerDirectives from './directives';
 import { init } from './hydration';
+import { rawStore, afterLoads } from './store';
 export { store } from './store';
 export { directive } from './hooks';
 export { h as createElement } from 'preact';
@@ -16,4 +17,5 @@ registerDirectives();
 
 document.addEventListener( 'DOMContentLoaded', async () => {
 	await init();
+	afterLoads.forEach( ( afterLoad ) => afterLoad( rawStore ) );
 } );

packages/interactivity/src/store.js

@@ -35,9 +35,25 @@ const getSerializedState = () => {
 	return {};
 };
 
+export const afterLoads = new Set();
+
 const rawState = getSerializedState();
 export const rawStore = { state: deepSignal( rawState ) };
 
+/**
+ * @typedef StoreProps Properties object passed to `store`.
+ * @property {Object} state State to be added to the global store. All the
+ *                          properties included here become reactive.
+ */
+
+/**
+ * @typedef StoreOptions Options object.
+ * @property {(store:any) => void} [afterLoad] Callback to be executed after the
+ *                                             Interactivity API has been set up
+ *                                             and the store is ready. It
+ *                                             receives the store as argument.
+ */
+
 /**
  * Extends the Interactivity API global store with the passed properties.
  *
@@ -76,11 +92,11 @@ export const rawStore = { state: deepSignal( rawState ) };
  * </div>
  * ```
  *
- * @param {Object} properties         Properties to be added to the global store.
- * @param {Object} [properties.state] State to be added to the global store. All
- *                                    the properties included here become reactive.
+ * @param {StoreProps}   properties Properties to be added to the global store.
+ * @param {StoreOptions} [options]  Options passed to the `store` call.
  */
-export const store = ( { state, ...block } ) => {
+export const store = ( { state, ...block }, { afterLoad } = {} ) => {
 	deepMerge( rawStore, block );
 	deepMerge( rawState, state );
+	if ( afterLoad ) afterLoads.add( afterLoad );
 };

test/e2e/specs/interactivity/store-afterload.spec.ts

@@ -0,0 +1,40 @@
+/**
+ * Internal dependencies
+ */
+import { test, expect } from './fixtures';
+
+test.describe( 'store afterLoad callbacks', () => {
+	test.beforeAll( async ( { interactivityUtils: utils } ) => {
+		await utils.activatePlugins();
+		await utils.addPostWithBlock( 'test/store-afterload' );
+	} );
+
+	test.beforeEach( async ( { interactivityUtils: utils, page } ) => {
+		await page.goto( utils.getLink( 'test/store-afterload' ) );
+	} );
+
+	test.afterAll( async ( { interactivityUtils: utils } ) => {
+		await utils.deactivatePlugins();
+		await utils.deleteAllPosts();
+	} );
+
+	test( 'run after the vdom and store are ready', async ( { page } ) => {
+		const allStoresReady = page.getByTestId( 'all-stores-ready' );
+		const vdomReady = page.getByTestId( 'vdom-ready' );
+
+		await expect( allStoresReady ).toHaveText( 'true' );
+		await expect( vdomReady ).toHaveText( 'true' );
+	} );
+
+	test( 'run once even if shared between several store calls', async ( {
+		page,
+	} ) => {
+		const afterLoadTimes = page.getByTestId( 'after-load-exec-times' );
+		const sharedAfterLoadTimes = page.getByTestId(
+			'shared-after-load-exec-times'
+		);
+
+		await expect( afterLoadTimes ).toHaveText( '1' );
+		await expect( sharedAfterLoadTimes ).toHaveText( '1' );
+	} );
+} );