// noprotect

async function streamingRead() {

  const response = await fetch('https://html.spec.whatwg.org');

  const find = 'J';

  const findCode = find.codePointAt(0);

  let bytes = 0;

​

  for await (const chunk of streamAsyncIterator(response.body)) {

    const index = chunk.indexOf(findCode);

    if (index != -1) {

      bytes += index;

      console.log(`Found ${find} at byte ${bytes}.`);

      break;

    }

    bytes += chunk.length;

  }

  response.body.cancel();

}

​

async function* streamAsyncIterator(stream) {

  // Get a lock on the stream

  const reader = stream.getReader();

​

  try {

    while (true) {

      // Read from the stream

      const {done, value} = await reader.read();

      // Exit if we're done

      if (done) return;

      // Else yield the chunk

      yield value;

    }

  }

  finally {

    reader.releaseLock();

  }

}

​

streamingRead();