Function readableByteStreamTee

lib/internal/webstreams/readablestream.js:1849–2119

(stream)

}

function readableByteStreamTee(stream) {
  assert(isReadableStream(stream));
  assert(isReadableByteStreamController(stream[kState].controller));

  let reader = new ReadableStreamDefaultReader(stream);
  let reading = false;
  let readAgainForBranch1 = false;
  let readAgainForBranch2 = false;
  let canceled1 = false;
  let canceled2 = false;
  let reason1;
  let reason2;
  let branch1;
  let branch2;
  const cancelDeferred = PromiseWithResolvers();

  function forwardReaderError(thisReader) {
    PromisePrototypeThen(
      readerClosedPromise(thisReader).promise,
      undefined,
      (error) => {
        if (thisReader !== reader) {
          return;
        }
        readableStreamDefaultControllerError(branch1[kState].controller, error);
        readableStreamDefaultControllerError(branch2[kState].controller, error);
        if (!canceled1 || !canceled2) {
          cancelDeferred.resolve();
        }
      },
    );
  }

  function pullWithDefaultReader() {
    if (isReadableStreamBYOBReader(reader)) {
      readableStreamBYOBReaderRelease(reader);
      reader = new ReadableStreamDefaultReader(stream);
      forwardReaderError(reader);
    }

    const readRequest = {
      [kChunk](chunk) {
        queueMicrotask(() => {
          readAgainForBranch1 = false;
          readAgainForBranch2 = false;
          const chunk1 = chunk;
          let chunk2 = chunk;

          if (!canceled1 && !canceled2) {
            try {
              chunk2 = cloneAsUint8Array(chunk);
            } catch (error) {
              readableByteStreamControllerError(
                branch1[kState].controller,
                error,
              );
              readableByteStreamControllerError(
                branch2[kState].controller,