What are streams, buffers and EventEmitter?

Definition:

A buffer is a container for raw bytes, while a stream processes a sequence of data in chunks. EventEmitter is a mechanism for registering listeners and notifying them when an event occurs. These tools work together in Node networking and file handling, where data can arrive gradually.

Key points:

• A buffer stores bytes; a stream moves data in chunks.

• Streams help process large files without loading everything at once.

• EventEmitter calls registered listeners synchronously when an event is emitted.

• Streams include readable, writable, duplex and transform types.

• Backpressure keeps a fast producer from overwhelming a slow consumer; simply using chunks does not remove the need to control flow.

Interview point:

• An EventEmitter notification is in-process and normally synchronous; it is not a durable background queue.