如何在没有 setInterval 的情况下“排队”请求一直运行？

Question

I am reading data in realtime from a device through http requests, however the way I am currently doing it is, something like this:

setInterval(() => {
  for (let request of requests) {
    await request.GetData();
  }
}, 1000);

However, sometimes there is lag in the network, and since there are 4-5 requests, sometimes they don't all finish within a second, so they start stacking up, until the device eventually starts to timeout, so I need to somehow get rid of the setInterval. Increasing the time is not an option.

Essentially, I want them to get stuck in an infinite loop and I can add an inner timer to let the requests run again when half a second or a second has passed since the last run, but how do I get them stuck in an infinite loop without blocking the rest of the application?

Or maybe a way to make setInterval wait for all requests to finish before starting to count the 1 second interval?

Answer 1

Try:

(async () => {
  while (true) {
    for (let request of requests) {
      await request.GetData();
    }

    await new Promise((resolve) => setTimeout(resolve, 1000));
  }
})();

This will only start waiting once all the requests are finished, preventing them from stacking up.

Alternatively, on the inside of the async function, use:

while (true) {
  await Promise.all(requests.map(request => request.GetData()));
  await new Promise((resolve) => setTimeout(resolve, 1000));
}

This is different because all the calls to request.GetData() will run concurrently, which may or may not be what you want.