Writing files in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What Node.js module is used to write files?

The fs module is used to write files in Node.js. It provides methods like writeFile and writeFileSync.

beginner

What is the difference between writeFile and writeFileSync?

writeFile writes files asynchronously without blocking the program, while writeFileSync writes files synchronously and blocks the program until done.

beginner

How do you handle errors when writing files asynchronously in Node.js?

You provide a callback function to writeFile that receives an error object if something goes wrong. You check if the error exists and handle it inside the callback.

beginner

What happens if the file does not exist when using writeFile?

If the file does not exist, writeFile creates it automatically before writing the content.

beginner

How can you write text content to a file using Node.js?

Use fs.writeFile('filename.txt', 'your text here', callback) to write text content to a file asynchronously.

Which Node.js method writes a file without blocking the program?

A fs.writeFileSync

B fs.appendFileSync

C fs.readFileSync

D fs.writeFile

fs.writeFile writes files asynchronously, so it does not block the program.

What does fs.writeFileSync do?

A Writes a file synchronously, blocking the program

B Reads a file synchronously

C Writes a file asynchronously

D Deletes a file

fs.writeFileSync writes files synchronously and blocks the program until done.

If the file does not exist, what happens when you use fs.writeFile?

A It ignores the write

B It throws an error

C It creates the file and writes content

D It appends to a different file

fs.writeFile creates the file if it does not exist before writing.

How do you know if an error happened during fs.writeFile?

A By checking the return value

B By checking the error argument in the callback

C By catching an exception

D By reading the file afterwards

The callback function receives an error argument if something goes wrong.

Which of these is a valid way to write 'Hello' to a file named 'greet.txt' asynchronously?

A fs.writeFile('greet.txt', 'Hello', () => {})

B fs.writeFileSync('greet.txt', 'Hello')

C fs.readFile('greet.txt', 'Hello')

D fs.appendFileSync('greet.txt', 'Hello')

fs.writeFile with a callback writes asynchronously.

Explain how to write text to a file asynchronously in Node.js and handle errors.

Think about the method that takes a filename, content, and a callback.

Describe the difference between synchronous and asynchronous file writing in Node.js.

Consider how the program behaves during file writing.