File System and Path¶

File System (fs module)¶

The fs module allows you to interact with the file system (read, write, update, delete files/directories).

const fs = require("fs");

Read a File (async)¶

fs.readFile("file.txt", "utf8", (err, data) => {
  if (err) throw err;
  console.log(data);
});

Read a File (sync)¶

const data = fs.readFileSync("file.txt", "utf8");
console.log(data);

Write a File (overwrite)¶

fs.writeFile("output.txt", "Hello world", (err) => {
  if (err) throw err;
  console.log("Written successfully");
});

Append to a File¶

fs.appendFile("output.txt", "\nNew line", (err) => {
  if (err) throw err;
});

Delete a File¶

fs.unlink("output.txt", (err) => {
  if (err) throw err;
});

Create a Directory¶

fs.mkdir("myFolder", (err) => {
  if (err) throw err;
});

Read Directory Contents¶

fs.readdir(".", (err, files) => {
  if (err) throw err;
  console.log(files);
});

Remove a Directory¶

fs.rmdir("myFolder", (err) => {
  if (err) throw err;
});

fs.promises (modern promise-based API)¶

const fsPromises = require("fs").promises;

async function readFile() {
  const data = await fsPromises.readFile("file.txt", "utf8");
  console.log(data);
}

Path Module¶

The path module is used to work with file and directory paths in a platform-independent way.

const path = require("path");

Common Methods¶

__dirname                // current directory
__filename               // current file path

path.basename(__filename)    // just file name
path.dirname(__filename)     // directory name
path.extname(__filename)     // file extension
path.join("folder", "file.txt")  // cross-platform path
path.resolve("folder", "file.txt") // absolute path

Example¶

const filePath = path.join(__dirname, "data", "info.txt");
console.log(filePath);

Summary¶

Task	Method
Read file	`fs.readFile`, `fs.readFileSync`
Write file	`fs.writeFile`, `fs.appendFile`
Delete file	`fs.unlink`
Read dir	`fs.readdir`
Work with paths	`path.join`, `path.basename`