File System

In this tutorial, we'll explore how to work with the file system on your computer using Node.js.

Node.js as a File Server

The Node.js file system module allows you to perform various operations on files, such as reading, creating, updating, deleting, and renaming files. To include the File System module, use the require() method:

var fs = require('fs');

Read Files

The fs.readFile() method is used to read files on your computer. Let's see an example of reading an HTML file:

var http = require('http');
var fs = require('fs');

http.createServer(function (req, res) {
  fs.readFile('demofile1.html', function(err, data) {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.write(data);
    return res.end();
  });
}).listen(8080);

Create Files

The File System module provides methods for creating new files, such as fs.appendFile(), fs.open(), and fs.writeFile(). Let's see examples of creating new files:

var fs = require('fs');

fs.appendFile('mynewfile1.txt', 'Hello content!', function (err) {
  if (err) throw err;
  console.log('Saved!');
});

var fs = require('fs');

fs.open('mynewfile2.txt', 'w', function (err, file) {
  if (err) throw err;
  console.log('Saved!');
});

var fs = require('fs');

fs.writeFile('mynewfile3.txt', 'Hello content!', function (err) {
  if (err) throw err;
  console.log('Saved!');
});

Update and Delete Files

The File System module also provides methods for updating and deleting files, such as fs.appendFile(), fs.writeFile(), and fs.unlink(). Let's see examples of updating and deleting files:

var fs = require('fs');

fs.appendFile('mynewfile1.txt', ' This is my text.', function (err) {
  if (err) throw err;
  console.log('Updated!');
});

var fs = require('fs');

fs.writeFile('mynewfile3.txt', 'This is my text', function (err) {
  if (err) throw err;
  console.log('Replaced!');
});

var fs = require('fs');

fs.unlink('mynewfile2.txt', function (err) {
  if (err) throw err;
  console.log('File deleted!');
});

Rename Files

To rename a file, use the fs.rename() method:

var fs = require('fs');

fs.rename('mynewfile1.txt', 'myrenamedfile.txt', function (err) {
  if (err) throw err;
  console.log('File Renamed!');
});

You can perform various file operations easily using these methods 📁