What is the purpose of the `highWaterMark` option when creating a readable stream?

Q: What is the purpose of the `highWaterMark` option when creating a readable stream?

The `highWaterMark` option determines the size (in bytes) of the internal buffer used by a readable stream. When the buffer is full, the readable stream will stop reading data from its source until the buffer has been drained. It helps control backpressure by specifying the maximum amount of data that can be buffered before pausing the source.

Difficulty: 5/10

stream buffering, backpressure, performance tuning

1
The highWaterMark option determines the size (in bytes) of the internal buffer used by a readable stream.
2
When the buffer is full, the readable stream will stop reading data from its source until the buffer has been drained.
3
It helps control backpressure by specifying the maximum amount of data that can be buffered before pausing the source.

Scenario Questions

0-2 years experience

2-5 years experience

1Your service streams JSON objects from a database to HTTP clients and you start seeing backpressure warnings. How would you adjust highWaterMark to mitigate this, and what trade‑offs are you making?

Follow-up Questions