fetch chunks: use the fetch and WHATWG Stream APIs to return an async generator of typed arrays given an URL

fetchChunks.js

async function* fetchChunks(...args) {
  let response = await fetch(...args);
  let reader = response.body.getReader(), state = {done:false};
  while (!state.done) {
    state = await reader.read();
    yield state.value;
  }
}