# In-memory File System Access (FSA) API implementation In-memory file-system with browser FSA API. Construct a new instance: ## Quick Start Create a new instance of FSA filesystem: ```ts import { fsa } from 'memfs/lib/fsa'; // Create a new filesystem. const { dir, core } = fsa({ mode: 'readwrite' }); // Create a folder and a file. const dir2 = await dir.getDirectoryHandle('new-folder', { create: true }); const file = await dir2.getFileHandle('file.txt', { create: true }); await (await file.createWritable()).write('Hello, world!'); // Export whole filesystem to JSON. console.log(core.toJSON()); // { '/new-folder/file.txt': 'Hello, world!' } ``` Create a new FSA filesystem from JSON: ```ts const { dir, core } = fsa({ mode: 'readwrite' }); // Import JSON. core.fromJSON( { 'documents/readme.txt': 'Welcome!', 'photos/vacation.jpg': Buffer.from('fake-jpg-data'), 'empty-folder': null, }, '/', ); // Use FSA API. const dir2 = await dir.getDirectoryHandle('documents'); const file = await dir2.getFileHandle('readme.txt'); const fileContent = await file.getFile(); console.log(await fileContent.text()); // 'Welcome!' ```