Question

Are file operations using the fs module synchronous or asynchronous?

I'm working with the fs module in Node.js and want to understand whether file operations are synchronous or asynchronous. Can someone clarify this?

Answer 1

The fs module in Node.js supports both synchronous and asynchronous file operations.

1. Asynchronous Operations

Definition: These operations do not block the execution of the program. The program may continue running other code while the file operation is being carried out. The result is handled by a callback function, a Promise, or async/await after the operation is finished.

Example: fs.readFile is an asynchronous method.

const fs = require('fs');fs.readFile('example.txt', 'utf8', (err, data) => {  if (err) {    console.error(err);    return;  }  console.log(data);});console.log('This will print first!');

Output:

"This will print first!" (immediate)

File content (later, when read operation completes)

2. Synchronous Operations

Definition: These operations block the execution of the program until the task completes. This means no further code runs until the file operation is finished.

Example: fs.readFileSync is a synchronous method.

const fs = require('fs');const data = fs.readFileSync('example.txt', 'utf8');console.log(data);console.log('This will print after the file is read.');

Output:

File content

"This will print after the file is read." (after the read operation)