# Learning Journal Node.js: writing to files

One of the ways to output in Node.js is to write directly to files in the local file system. One method that Node.js provides is `fs.writeFileSync`. This is a blocking method that appears to write string data to a given file, using the file name as a reference.

The `fs.writeFileSync` command takes two arguments/parameters:

1. file name
    
2. text string
    

It requires that the fs (file system) module be imported, and then will write the text string directly to the file name. What's interesting to me about this, however, is that it will also overwrite any existing data that's in the file.

For example:

```javascript
// app.js
const fs = require('fs')

fs.writeFileSync('notes.txt', 'This was written in Node.js!')
```

The output of this JavaScript execution is:

1. The file `notes.txt` is created as a sibling file to `app.js` (the code above)
    
2. The `notes.txt` file contains the `This was written in Node.js` string value
    

Interestingly, the `fs.writeFileSync` method will also overwrite any existing data in the file. For example:

```javascript
// app.js
const fs = require('fs')

const fileName = 'notes.txt'

fs.writeFileSync(fileName, 'This was written in Node.js!')
fs.writeFileSync(fileName, 'My name is Nathan')
```

The resulting value in `notes.txt` will only be the `My name is Nathan` string, rather than `This was written in Node.js!My name is Nathan` .

If you're trying to continuously write to the file, you should instead use `fs.appendFile` or `fs.appendFileSync` so that new values are added to the file, rather than overwriting them.