Simple file writer with atomic writing and race condition prevention.
Can be used as a drop-in replacement to fs.writeFile().
Built on graceful-fs and used in lowdb.
npm install steno --save
```javascript const steno = require('steno')
steno.writeFile('file.json', data, err => { if (err) throw err }) ```
Let's say you have a server and want to save data to disk:
```javascript var data = { counter: 0 }
server.post('/', (req, res) => { // Increment counter ++data.counter
// Save data asynchronously fs.writeFile('data.json', JSON.stringify(data), err => { if (err) throw err res.end() }) }) ```
Now if you have many requests, for example 1000, there's a risk that you end up with:
```javascript // In your server data.counter === 1000
// In data.json data.counter === 865 // ... or any other value ```
Why? Because, fs.write doesn't guarantee that the call order will be kept. Also, if the server is killed while data.json is being written, the file can get corrupted.
```javascript server.post('/increment', (req, res) => { ++data.counter
steno.writeFile('data.json', JSON.stringify(data), err => { if (err) throw err res.end() }) }) ```
With steno you'll always have the same data in your server and file. And in case of a crash, file integrity will be preserved.
if needed, you can also use steno.writeFileSync() which offers atomic writing too.
Important: works only in a single instance of Node.
MIT - Typicode