Challenge 3 — Solution

Task: Write a function that checks a fetch Response object's status
and, if it's 429, logs "Rate limited — backing off" and waits 2
seconds (using a Promise + setTimeout) before returning a retry
signal; otherwise it returns the response's parsed JSON normally.
Test it with a mocked response object of { status: 429 }.

async function handleResponse(response) {
    if (response.status === 429) {
        console.log("Rate limited — backing off");
        await new Promise(resolve => setTimeout(resolve, 2000));
        return { retry: true };
    }

    return response.json();
}

const mockResponse = { status: 429 };

handleResponse(mockResponse).then(result => {
    console.log(result);
});


Expected output (after a 2-second pause):

Rate limited — backing off
{ retry: true }

Notes:
- The mocked response object only has a status field, which is all
  this function actually needs to check — a real fetch Response
  object would have a json() method too, but that's deliberately
  never called on the 429 path, since it isn't needed there.
- new Promise(resolve => setTimeout(resolve, 2000)) is the standard
  way to create a plain "wait this long" delay that works with
  await — there's no built-in sleep() function in JavaScript, so
  this pattern fills that gap.
- A real implementation would call handleResponse again after the
  delay (using the { retry: true } signal to decide whether to
  re-fetch), which this challenge doesn't implement, but the
  function's return value is designed to support that next step.