Only load Gutenberg Polyfill in Gutenberg pages (#6849)

lib/client-assets.php

@@ -1093,9 +1093,25 @@ function gutenberg_editor_scripts_and_styles( $hook ) {
  * Remove this in Gutenberg 3.1
  */
 function polyfill_blocks_module_in_scripts() {
- if ( is_admin() ) {
- wp_enqueue_script( 'wp-editor' );
+ global $post;
+
+ if ( ! is_admin() ) {
+ return;
  }
+
+ if ( get_current_screen()->base !== 'post' ) {
+ return;
+ }
+
+ if ( isset( $_GET['classic-editor'] ) ) {
+ return;
+ }
+
+ if ( ! gutenberg_can_edit_post( $post ) ) {
+ return;
+ }
+
+ wp_enqueue_script( 'wp-editor' );
 }
 
 add_action( 'enqueue_block_editor_assets', 'polyfill_blocks_module_in_scripts', 9 );

test/e2e/specs/classic-editor.test.js

@@ -0,0 +1,27 @@
+/**
+ * Internal dependencies
+ */
+import '../support/bootstrap';
+import { visitAdmin, newDesktopBrowserPage } from '../support/utils';
+
+describe( 'classic editor', () => {
+ beforeAll( async () => {
+ await newDesktopBrowserPage();
+ await visitAdmin( 'post-new.php', 'classic-editor' );
+ } );
+
+ it( 'Should work properly', async () => {
+ // Click visual editor
+ await page.click( '#content-tmce' );
+ await page.click( '#content_ifr' );
+
+ // type some random text
+ await page.keyboard.type( 'Typing in classic editor' );
+
+ // Swtich to HTML mode
+ await page.click( '#content-html' );
+
+ const textEditorContent = await page.$eval( '.wp-editor-area', ( element ) => element.value );
+ expect( textEditorContent ).toEqual( 'Typing in classic editor' );
+ } );
+} );