Introduction to fs-extra

fs-extra is a comprehensive, lightweight, and flexible file system library for Node.js. It extends the built-in fs module, providing additional features and making file manipulation easier and more powerful. In this guide, we’ll explore dozens of useful APIs provided by fs-extra with code snippets and an example app.

Installation

  
  npm install fs-extra
  

API Examples

Copy Files and Directories

The copy method allows you to copy files or directories from one location to another:

  
  const fs = require('fs-extra');

  fs.copy('/tmp/myfile', '/tmp/mynewfile')
    .then(() => console.log('Copy successful!'))
    .catch(err => console.error(err));
  

Remove Files and Directories

The remove method deletes files or directories:

  
  fs.remove('/tmp/myfile')
    .then(() => console.log('File deleted!'))
    .catch(err => console.error(err));
  

Ensure File

The ensureFile method creates a file if it doesn’t already exist:

  
  fs.ensureFile('/tmp/this/path/does/not/exist/file.txt')
    .then(() => console.log('File created!'))
    .catch(err => console.error(err));
  

Ensure Directory

The ensureDir method creates a directory if it doesn’t already exist:

  
  fs.ensureDir('/tmp/this/path/does/not/exist')
    .then(() => console.log('Directory created!'))
    .catch(err => console.error(err));
  

Read JSON

The readJson method reads a JSON file and parses its content:

  
  fs.readJson('/tmp/data.json')
    .then(data => console.log(data))
    .catch(err => console.error(err));
  

Write JSON

The writeJson method writes an object to a JSON file:

  
  const data = { name: 'John', age: 30 };
  fs.writeJson('/tmp/data.json', data)
    .then(() => console.log('JSON written!'))
    .catch(err => console.error(err));
  

Moving Files

The move method moves a file or directory:

  
  fs.move('/tmp/file', '/tmp/newfile')
    .then(() => console.log('File moved!'))
    .catch(err => console.error(err));
  

Emptying Directories

The emptyDir method empties a directory, removing all its contents:

  
  fs.emptyDir('/tmp/mydir')
    .then(() => console.log('Directory emptied!'))
    .catch(err => console.error(err));
  

Example Application

Let’s create an example Node.js application that uses several fs-extra APIs:

  
  const fs = require('fs-extra');

  async function main() {
    try {
      // Ensure directory exists
      await fs.ensureDir('/tmp/app');

      // Write some data to a JSON file
      const data = { name: 'MyApp', version: '1.0.0' };
      await fs.writeJson('/tmp/app/config.json', data);
      console.log('Config file created!');

      // Copy the config file
      await fs.copy('/tmp/app/config.json', '/tmp/app/config.copy.json');
      console.log('Config file copied!');

      // Read the copied JSON file
      const copiedData = await fs.readJson('/tmp/app/config.copy.json');
      console.log('Copied config data:', copiedData);

      // Move the copied file
      await fs.move('/tmp/app/config.copy.json', '/tmp/app/config.new.json');
      console.log('Copied config file moved!');

      // Empty the directory
      await fs.emptyDir('/tmp/app');
      console.log('App directory emptied!');
    } catch (err) {
      console.error(err);
    }
  }

  main();
  

This example demonstrates various fs-extra functionalities including creating directories, writing JSON files, copying files, reading JSON data, moving files, and emptying directories.

Using fs-extra simplifies complex file system operations and enhances productivity when building Node.js applications.

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