[ptx]

Yup, this is what WHATWG's Streams spec[0] (linked in the article) says. It defines backpressure as a "process of normalizing flow from the original source according to how fast the chain can process chunks" where the reader "propagates a signal backwards through the pipe chain".

Mozilla's documentation[1] similarly defines backpressure as "the process by which a single stream or a pipe chain regulates the speed of reading/writing".

The article confuses backpressure (the signal used for regulation of the flow) with the reason backpressure is needed (producers and consumers working at different speeds). It should be fairly clear from the metaphor, I would have thought: With a pipe of unbounded size there is no pressure. The pressure builds up in a fixed-size pipe when consumer is slower than producer, which in turn slows down the producer. (Or the pipe explodes, or springs a leak and has to drop data on the ground.)

[0] https://streams.spec.whatwg.org/#pipe-chains

[1] https://developer.mozilla.org/en-US/docs/Web/API/Streams_API...