Node.js Streams & Buffers 2

Question 1

Which stream base class should you extend to implement a custom stream that both reads input and produces transformed output?

Accepted Answer

stream.Transform

Answer

stream.Readable

Answer

stream.Duplex

Answer

stream.PassThrough

Question 2

What is the purpose of the highWaterMark option when creating a Node.js stream?

Accepted Answer

Defines the internal buffer size threshold before backpressure is applied

Answer

Sets the maximum file size that can be streamed

Answer

Limits the number of concurrent stream instances

Answer

Sets the read timeout duration for the stream

Question 3

Which internal method must you implement when subclassing stream.Readable to provide data to consumers?

Accepted Answer

_read()

Answer

_write()

Answer

_transform()

Answer

_flush()

Question 4

Why is stream.pipeline() preferred over readable.pipe() for production code?

Accepted Answer

It handles errors and automatically destroys all streams in the pipeline

Answer

It provides better throughput on large files

Answer

It supports older Node.js versions that lack pipe()

Answer

It enables bidirectional data flow between streams

Question 5

How do you create a Buffer from a hexadecimal string in Node.js?

Accepted Answer

Buffer.from('deadbeef', 'hex')

Answer

Buffer.from('deadbeef')

Answer

Buffer.fromHex('deadbeef')

Answer

new Buffer('deadbeef', 16)

Question 6

What does calling readable.push(null) inside a custom Readable stream signify?

Accepted Answer

Signals the end of the stream (EOF)

Answer

Clears the stream's internal buffer

Answer

Temporarily pauses the stream

Answer

Resets the stream to its initial state

Question 7

In Node.js object mode streams, what type of data can be passed as a chunk?

Accepted Answer

Any JavaScript value including objects, arrays, and primitives

Answer

Fixed-size byte chunks only

Answer

UTF-8 encoded strings only

Answer

Only JSON-serializable data structures