Awesome Open Source
Awesome Open Source


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


const steno = require('steno')

steno.writeFile('file.json', data, err => {
  if (err) throw err

The problem it solves

Without steno

Let's say you have a server and want to save data to disk:

var data = { counter: 0 }'/', (req, res) => {
  // Increment counter

  // Save data asynchronously
  fs.writeFile('data.json', JSON.stringify(data), err => {
    if (err) throw err

Now if you have many requests, for example 1000, there's a risk that you end up with:

// 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.

With steno'/increment', (req, res) => {

  steno.writeFile('data.json', JSON.stringify(data), err => {
    if (err) throw err

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

Get A Weekly Email With Trending Projects For These Topics
No Spam. Unsubscribe easily at any time.
javascript (67,985
file (137
fs (29
atomic (23
writer (23
safe (15

Find Open Source By Browsing 7,000 Topics Across 59 Categories