Promise JS

Promise.all()
Body.json()

Promise.all(arr)
  .then(responses => {
    // Get a JSON object from each of the responses
    return Promise.all(responses.map(response => response.json()));
  })

• Request 和 fetch 直接帶網址差在哪裡？
  Request()
  https://developer.mozilla.org/en-US/docs/Web/API/Request/Request