All: Fixes #13291: Improve performance of item deserialization

packages/lib/models/BaseItem.test.ts

@@ -1,3 +1,4 @@
+import { Second } from '@joplin/utils/time';
 import { afterAllCleanUp, setupDatabaseAndSynchronizer, switchClient, syncTargetId, synchronizerStart, msleep } from '../testing/test-utils';
 import BaseItem from './BaseItem';
 import Folder from './Folder';
@@ -42,6 +43,19 @@ describe('BaseItem', () => {
 		expect(unserialized2.title).toBe(folder2.title);
 	});
 
+	it.each([
+		'',
+		'\n\na\nb\nc\nç\nTest!\n Testing. \n',
+		'Test! ☺',
+		'Test! ☺\n\n\n',
+	])('should not modify body when unserializing (body: %j)', async (body) => {
+		const note = await Note.save({ title: 'note1', body });
+
+		expect(await Note.unserialize(await Note.serialize(note))).toMatchObject({
+			body,
+		});
+	});
+
 	it('should correctly unserialize note timestamps', async () => {
 		const folder = await Folder.save({ title: 'folder' });
 		const note = await Note.save({ title: 'note', parent_id: folder.id });
@@ -55,6 +69,22 @@ describe('BaseItem', () => {
 		expect(unserialized.user_updated_time).toEqual(note.user_updated_time);
 	});
 
+	it('should unserialize a very large note quickly', async () => {
+		const folder = await Folder.save({ title: 'folder' });
+		const note = await Note.save({ title: 'note', parent_id: folder.id });
+
+		const serialized = await Note.serialize({
+			...note,
+			// 2 MiB
+			body: '\n.'.repeat(1 * 1024 * 1024),
+		});
+
+		const start = performance.now();
+		await Note.unserialize(serialized);
+		// Locally, this passes in in < 2s, so 30s should be a safe upper bound.
+		expect(performance.now() - start).toBeLessThan(30 * Second);
+	});
+
 	it('should serialize geolocation fields', async () => {
 		const folder = await Folder.save({ title: 'folder' });
 		let note = await Note.save({ title: 'note', parent_id: folder.id });

packages/lib/models/BaseItem.ts

@@ -578,28 +578,24 @@ export default class BaseItem extends BaseModel {
 		const lines = content.split('\n');
 		// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Old code before rule was applied
 		let output: any = {};
-		let state = 'readingProps';
-		const body: string[] = [];
+		let body: string[] = [];
 
 		for (let i = lines.length - 1; i >= 0; i--) {
 			let line = lines[i];
 
-			if (state === 'readingProps') {
-				line = line.trim();
+			line = line.trim();
 
-				if (line === '') {
-					state = 'readingBody';
-					continue;
-				}
-
-				const p = line.indexOf(':');
-				if (p < 0) throw new Error(`Invalid property format: ${line}: ${content}`);
-				const key = line.substr(0, p).trim();
-				const value = line.substr(p + 1).trim();
-				output[key] = value;
-			} else if (state === 'readingBody') {
-				body.splice(0, 0, line);
+			// Props are separated from the body by a single blank line
+			if (line === '') {
+				body = lines.slice(0, i);
+				break;
 			}
+
+			const p = line.indexOf(':');
+			if (p < 0) throw new Error(`Invalid property format: ${line}: ${content}`);
+			const key = line.substr(0, p).trim();
+			const value = line.substr(p + 1).trim();
+			output[key] = value;
 		}
 
 		if (!output.type_) throw new Error(`Missing required property: type_: ${content}`);