fix(app): insert a newline on Enter inside code blocks (#2674)

fluxer_app/src/features/lexical/composer/ComposerCodeIndent.test.ts

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import {registerComposerCodeIndent} from '@app/features/lexical/composer/ComposerCodeIndent';
+import {
+	$getComposerDisplayText,
+	$replaceComposerRange,
+	$selectComposerRange,
+} from '@app/features/lexical/composer/composerOffsets';
+import {ComposerMentionNode} from '@app/features/lexical/composer/nodes/ComposerMentionNode';
+import {createEditor, KEY_TAB_COMMAND} from 'lexical';
+import {describe, expect, it, vi} from 'vitest';
+
+vi.mock('@app/features/lexical/composer/nodes/ComposerMentionPill', () => ({ComposerMentionPill: () => null}));
+vi.mock('@app/features/lexical/composer/nodes/ComposerCustomEmoji', () => ({ComposerCustomEmoji: () => null}));
+vi.mock('@app/features/lexical/composer/nodes/ComposerStandardEmoji', () => ({ComposerStandardEmoji: () => null}));
+
+describe('registerComposerCodeIndent', () => {
+	it('indents a block opened after a mention whose name holds a backtick', () => {
+		const editor = createEditor({
+			namespace: 'composer-code-indent-test',
+			nodes: [ComposerMentionNode],
+			onError: (error) => {
+				throw error;
+			},
+		});
+		registerComposerCodeIndent(editor, {current: false});
+		editor.update(
+			() => {
+				$replaceComposerRange(
+					0,
+					0,
+					{kind: 'mention', mentionType: 'user', id: '1', display: '@`bob', wire: '<@1>'},
+					{trailing: false},
+				);
+				$replaceComposerRange(5, 5, {kind: 'text', text: ' hi ```js\ncode'}, {leading: false, trailing: false});
+				$selectComposerRange(19, 19);
+			},
+			{discrete: true},
+		);
+		const event = Object.assign(new Event('keydown', {cancelable: true}), {shiftKey: false}) as KeyboardEvent;
+		expect(editor.dispatchCommand(KEY_TAB_COMMAND, event)).toBe(true);
+		expect(editor.read(() => $getComposerDisplayText())).toBe('@`bob hi ```js\ncode\t');
+	});
+});