Node.js Streams & Buffers

Question 1

What is the default string encoding used when creating a Buffer from a string in Node.js?

Accepted Answer

utf8

Answer

ascii

Answer

base64

Answer

latin1

Question 2

Which Node.js stream type is used exclusively for reading data?

Accepted Answer

Readable

Answer

Writable

Answer

Duplex

Answer

Transform

Question 3

What method connects a Readable stream to a Writable stream so data flows automatically?

Accepted Answer

readable.pipe(writable)

Answer

readable.connect(writable)

Answer

readable.forward(writable)

Answer

writable.receive(readable)

Question 4

What is the key difference between Buffer.alloc(size) and Buffer.allocUnsafe(size)?

Accepted Answer

allocUnsafe is faster but may contain old memory data; alloc zero-fills the buffer

Answer

alloc is faster but may contain old memory data; allocUnsafe zero-fills the buffer

Answer

They behave identically in modern Node.js versions

Answer

allocUnsafe throws an error if sufficient memory is unavailable

Question 5

In Node.js streams, what is 'backpressure'?

Accepted Answer

A flow-control mechanism that slows the producer when the consumer cannot keep up

Answer

An error thrown when a stream closes unexpectedly

Answer

A compression technique applied before data is transmitted

Answer

The event emitted when a Readable stream buffer overflows

Question 6

How do you convert a Node.js Buffer to a UTF-8 encoded string?

Accepted Answer

buffer.toString('utf8')

Answer

buffer.stringify()

Answer

buffer.decode('utf-8')

Answer

String.fromBuffer(buffer)

Question 7

What event does a Readable stream emit after all data has been consumed and the stream has closed?

Accepted Answer

'end'

Answer

'close'

Answer

'finish'

Answer

'done'