Function watchErrored

lib/internal/webstreams/readablestream.js:1586–1591

(stream, promise, action)

  }

  function watchErrored(stream, promise, action) {
    if (stream[kState].state === 'errored')
      action(stream[kState].storedError);
    else
      PromisePrototypeThen(promise, undefined, action);
  }

  function watchClosed(stream, promise, action) {
    if (stream[kState].state === 'closed')