Writing files in Node.js

Writing to files in Node.js is fairly easy thanks to provided File System APIs, node fs.

Asynchronously writes data to a file, replacing the file if it already exists. data can be a string or a buffer.

The encoding option is ignored if data is a buffer. It defaults to 'utf8'.

Example:

fs.writeFile('message.txt', 'Hello Node.js', function(err) {
  if (err) throw err;
  console.log('The file has been saved!');
});

Full Example:

1.  import file system module

var fs = require('fs')

2.  Now use fs to create a new file and write into it

fs.writeFile("/tmp/test.json", "{'key':'value'}", function(err) {
    if(error) {
        return console.log(error);
    }
    console.log("successfully saved test.json file");
});

Now Asynchronously reads the entire contents of a file.

fs.readFile("/tmp/test.json", function(err, data) {
  if (err) throw err;
  console.log(data);
});