ReadableStream: getReader()

getReader()
getReader(options)

function fetchStream() {
  const reader = stream.getReader();
  let charsReceived = 0;

  // read()  promise 
  reader.read().then(function processText({ done, value }) {
    // 2
    // done -  true
    // value -  done  true  undefined
    if (done) {
      console.log("Stream complete");
      para.textContent = value;
      return;
    }

    //  Uint8Array 
    charsReceived += value.length;
    const chunk = value;
    let listItem = document.createElement("li");
    listItem.textContent = `Received ${charsReceived} characters so far. Current chunk = ${chunk}`;
    list2.appendChild(listItem);

    result += chunk;

    // 
    return reader.read().then(processText);
  });
}