node js add to file code example

Example 1: How to append to a file in Node?

// Asynchronously:
const fs = require('fs');

fs.appendFile('message.txt', 'data to append', function (err) {
  if (err) throw err;
  console.log('Saved!');
});

// Synchronously:
const fs = require('fs');

fs.appendFileSync('message.txt', 'data to append');

Example 2: fs.writefile

const fs = require('fs');

fs.writeFile("/tmp/test", "Hey there!", function(err) {
    if(err) {
        return console.log(err);
    }
    console.log("The file was saved!");
}); 

// Or
fs.writeFileSync('/tmp/test-sync', 'Hey there!');