Non readable stream should throw when errored while not readable

[ronag]

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
}

[ronag]

@jasnell @nodejs/streams

[ofirbarak]

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

[aduh95]

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.

[aduh95]

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.

[jasnell]

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

[aduh95]

Fixed by mdn/content#13581.