const url = http1270018000apichat-gpt$prompt; fetchurl thenresponse = const reader = responsebodygetReader; return new ReadableStream star

To handle errors in this code, you can add a .catch() method after the .then() chain. For example:

const url = `http://127.0.0.1:8000/api/chat-gpt/${prompt}`;
fetch(url)
  .then(response => {
    // ...
  })
  .then(stream => {
    // ...
  })
  .catch(error => {
    console.error(error);
    // handle the error here, e.g. display an error message to the user
  });

This will catch any errors that occur during the fetch request, the stream processing, or the promise chain itself. You can then handle the error in whatever way makes sense for your application.