Desktop: Resolves #5762: Rich Text Editor: Add eight spaces when pressing tab

.eslintignore

@@ -299,6 +299,7 @@ packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/types.js
 packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useContextMenu.js
 packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useLinkTooltips.js
 packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useScroll.js
+packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useTabIndenter.js
 packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useWebViewApi.js
 packages/app-desktop/gui/NoteEditor/NoteEditor.js
 packages/app-desktop/gui/NoteEditor/NoteTitle/NoteTitleBar.js

.gitignore

@@ -276,6 +276,7 @@ packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/types.js
 packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useContextMenu.js
 packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useLinkTooltips.js
 packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useScroll.js
+packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useTabIndenter.js
 packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useWebViewApi.js
 packages/app-desktop/gui/NoteEditor/NoteEditor.js
 packages/app-desktop/gui/NoteEditor/NoteTitle/NoteTitleBar.js

packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/TinyMCE.tsx

@@ -38,6 +38,7 @@ const md5 = require('md5');
 const { clipboard } = require('electron');
 const supportedLocales = require('./supportedLocales');
 import { hasProtocol } from '@joplin/utils/url';
+import useTabIndenter from './utils/useTabIndenter';
 
 const logger = Logger.create('TinyMCE');
 
@@ -128,6 +129,7 @@ const TinyMCE = (props: NoteBodyEditorProps, ref: any) => {
 
 	usePluginServiceRegistration(ref);
 	useContextMenu(editor, props.plugins, props.dispatch, props.htmlToMarkdown, props.markupToHtml);
+	useTabIndenter(editor);
 
 	// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Old code before rule was applied
 	const dispatchDidUpdate = (editor: any) => {
@@ -629,6 +631,7 @@ const TinyMCE = (props: NoteBodyEditorProps, ref: any) => {
 				icons_url: 'gui/NoteEditor/NoteBody/TinyMCE/icons.js',
 				plugins: 'noneditable link joplinLists hr searchreplace codesample table',
 				noneditable_noneditable_class: 'joplin-editable', // Can be a regex too
+				iframe_aria_text: _('Rich Text editor. Press Escape then Tab to escape focus.'),
 
 				// #p: Pad empty paragraphs with   to prevent them from being removed.
 				// *[*]: Allow all elements and attributes -- we already filter in sanitize_html

packages/app-desktop/gui/NoteEditor/NoteBody/TinyMCE/utils/useTabIndenter.ts

@@ -0,0 +1,76 @@
+import { useEffect } from 'react';
+import type { Editor, EditorEvent } from 'tinymce';
+
+const useTabIndenter = (editor: Editor) => {
+	useEffect(() => {
+		if (!editor) return () => {};
+
+		const canChangeIndentation = () => {
+			const selectionElement = editor.selection.getNode();
+			// List items and tables have their own tab key handlers.
+			return !selectionElement.closest('li, table') && !editor.readonly;
+		};
+
+		const getSpacesBeforeSelectionRange = (maxLength: number) => {
+			const selectionRange = editor.selection.getRng();
+
+			let rangeStart = selectionRange.startOffset;
+			let outputRange = selectionRange.cloneRange();
+			while (rangeStart >= 0) {
+				rangeStart--;
+
+				const lastRange = outputRange.cloneRange();
+				outputRange.setStart(outputRange.startContainer, Math.max(rangeStart, 0));
+				const rangeContent = outputRange.toString();
+				const isWhitespace = rangeContent.match(/^\s*$/);
+				if (!isWhitespace || rangeContent.length > maxLength) {
+					outputRange = lastRange;
+					break;
+				}
+			}
+
+			return outputRange;
+		};
+
+		const indentLengthChars = 8;
+		let indentHtml = '';
+		for (let i = 0; i < indentLengthChars; i++) {
+			indentHtml += '&nbsp;';
+		}
+
+		let lastKeyWasEscape = false;
+
+		const eventHandler = (event: EditorEvent<KeyboardEvent>) => {
+			if (!event.isDefaultPrevented() && event.key === 'Tab' && canChangeIndentation() && !lastKeyWasEscape) {
+				if (!event.shiftKey) {
+					editor.execCommand('mceInsertContent', false, indentHtml);
+					event.preventDefault();
+				} else {
+					const selectionRange = editor.selection.getRng();
+					if (selectionRange.collapsed) {
+						const spacesRange = getSpacesBeforeSelectionRange(indentLengthChars);
+
+						const hasAtLeastOneSpace = spacesRange.toString().match(/^\s+$/);
+						if (hasAtLeastOneSpace) {
+							editor.selection.setRng(spacesRange);
+							editor.execCommand('Delete', false);
+							event.preventDefault();
+						}
+					}
+				}
+			} else if (event.key === 'Escape' && !event.shiftKey && !event.altKey && !event.metaKey && !event.ctrlKey) {
+				// For accessibility, let Escape followed by tab escape the focus trap.
+				lastKeyWasEscape = true;
+			} else if (event.key !== 'Shift') { // Allows Esc->Shift+Tab to escape the focus trap.
+				lastKeyWasEscape = false;
+			}
+		};
+
+		editor.on('keydown', eventHandler);
+		return () => {
+			editor.off('keydown', eventHandler);
+		};
+	}, [editor]);
+};
+
+export default useTabIndenter;

packages/app-desktop/integration-tests/richTextEditor.spec.ts

@@ -82,5 +82,42 @@ test.describe('richTextEditor', () => {
 		expect(await openPathResult).toContain(basename(pathToAttach));
 	});
 
+	test('pressing Tab should indent', async ({ mainWindow }) => {
+		const mainScreen = new MainScreen(mainWindow);
+		await mainScreen.createNewNote('Testing tabs!');
+		const editor = mainScreen.noteEditor;
+
+		await editor.toggleEditorsButton.click();
+		await editor.richTextEditor.click();
+
+		await mainWindow.keyboard.type('This is a');
+		// Tab should add spaces
+		await mainWindow.keyboard.press('Tab');
+		await mainWindow.keyboard.type('test.');
+
+		// Shift-tab should remove spaces
+		await mainWindow.keyboard.press('Tab');
+		await mainWindow.keyboard.press('Tab');
+		await mainWindow.keyboard.press('Shift+Tab');
+		await mainWindow.keyboard.type('Test!');
+
+		// Escape then tab should move focus
+		await mainWindow.keyboard.press('Escape');
+		await expect(editor.richTextEditor).toBeFocused();
+		await mainWindow.keyboard.press('Tab');
+		await expect(editor.richTextEditor).not.toBeFocused();
+
+		// After re-focusing the editor, Tab should indent again.
+		await mainWindow.keyboard.press('Shift+Tab');
+		await expect(editor.richTextEditor).toBeFocused();
+		await mainWindow.keyboard.type(' Another:');
+		await mainWindow.keyboard.press('Tab');
+		await mainWindow.keyboard.type('!');
+
+		// After switching back to the Markdown editor,
+		await expect(editor.toggleEditorsButton).not.toBeDisabled();
+		await editor.toggleEditorsButton.click();
+		await expect(editor.codeMirrorEditor).toHaveText('This is a        test.        Test! Another:        !');
+	});
 });