Reading files synchronously in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What Node.js module do you use to read files synchronously?

You use the fs module, which stands for 'file system'. It provides methods to work with files, including reading them synchronously.

beginner

What is the method to read a file synchronously in Node.js?

The method is fs.readFileSync(path, options). It reads the entire file content and returns it directly, blocking the program until done.

intermediate

What happens to your program when you use fs.readFileSync?

The program pauses and waits until the file is fully read. This means no other code runs during this time, which can slow down your app if the file is large.

beginner

How do you specify the file encoding when reading a file synchronously?

You pass an options object or string as the second argument to fs.readFileSync. For example, { encoding: 'utf8' } or simply 'utf8' to get a string instead of a buffer.

intermediate

Why might you avoid using synchronous file reading in a web server?

Because synchronous reading blocks the entire server process, making it unresponsive to other requests until the file is read. This hurts performance and user experience.

Which method reads a file synchronously in Node.js?

A fs.readFile()

B fs.readFileSync()

C fs.open()

D fs.writeFileSync()

fs.readFileSync() reads files synchronously, blocking the program until done.

What does fs.readFileSync return if you specify encoding 'utf8'?

A A string with file content

B Undefined

C An error object

D A Buffer object

Specifying 'utf8' encoding returns the file content as a string.

What is a downside of using synchronous file reading in Node.js?

A It uses too much memory

B It requires callbacks

C It reads files too fast

D It blocks the event loop

Synchronous reading blocks the event loop, stopping other code from running.

Which module must you import to use readFileSync?

A fs

B path

C http

D os

The fs module provides file system methods including readFileSync.

If you omit encoding in fs.readFileSync, what type is returned?

A String

B Number

C Buffer

D Boolean

Without encoding, readFileSync returns a Buffer object.

Explain how to read a file synchronously in Node.js and what happens during this operation.

Think about the method name and what synchronous means for program flow.

Describe why synchronous file reading might be a problem in a Node.js web server.

Consider how Node.js handles multiple users at once.