Non readable stream should throw when errored while not readable

https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamDefaultController/error#exceptions

TypeError
The source object is not a ReadableStreamDefaultController, or the stream is not readable for some other reason.

const { ReadableStream } = require('stream/web')

let c
const s = new ReadableStream({
  start (controller) {
    c = controller
  }
})

c.close()

try {
  c.error()
} catch (err) {
  console.error(err) // This should log an error
}

@jasnell

@jasnell @nodejs/streams

But it says also we can call error even when the stream is not readable. Maybe a mistake in the doc?

The above snippet doesn't log an error in any of the WHATWG stream implementation (I've tried Deno, Firefox, Safari, and Chromium), whatever the spec says I think we're good as long as all the implementation are aligned.

Maybe the MDN page is wrong, looking at the spec it says:

The error(e) method steps are:
Perform ! ReadableStreamDefaultControllerError(this, e).

ReadableStreamDefaultControllerError(controller, e) performs the following steps:
Let stream be controller.[[stream]].

If stream.[[state]] is not "readable", return.

Perform ! ResetQueue(controller).

Perform ! ReadableStreamDefaultControllerClearAlgorithms(controller).

Perform ! ReadableStreamError(stream, e).

It says the method should return, not throw an exception. I'll open a PR to mdn/content to fix the page.

Yeah, as surprising as it may be, the behavior here is correct and MDN is wrong.

Fixed by mdn/content#13581.

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Non readable stream should throw when errored while not readable #39756

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Non readable stream should throw when errored while not readable #39756

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ronag commented on Aug 13, 2021

ofirbarak commented on Nov 21, 2021

aduh95 commented on Mar 6, 2022

aduh95 commented on Mar 6, 2022

jasnell commented on Mar 6, 2022

aduh95 commented on Mar 6, 2022

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