Nodejs Guide

How to Write Files in Node.js?

1. Definition

In Node.js, files are written using the built-in fs (File System) module. It allows you to create new files or overwrite existing ones with data.

2. Methods to Write Files

  • fs.writeFile(): Asynchronous method
  • fs.writeFileSync(): Synchronous method
  • fs.appendFile(): Adds data to existing file

3. Asynchronous Example

const fs = require("fs");

fs.writeFile("example.txt", "Hello Node.js", (err) => {
  if (err) throw err;
  console.log("File written successfully");
});

4. Synchronous Example

const fs = require("fs");

fs.writeFileSync("example.txt", "Hello Node.js");
console.log("File written successfully");

5. Append Data Example

const fs = require("fs");

fs.appendFile("example.txt", "\nNew Data Added", (err) => {
  if (err) throw err;
  console.log("Data appended successfully");
});

6. Difference Between Async and Sync

  • Async: Non-blocking, better for performance
  • Sync: Blocking, used for simple tasks

7. Advantages

  • Easy file creation and modification
  • Supports asynchronous operations
  • Built-in module (no installation needed)