[removed] Function that retries with setTimeout

Question

I have a function downloadItem that may fail for network reasons, I want to be able to retry it a few times before actually rejecting that item. The retries nee

Answer 1

There is no need to create new promises to handle this. Assuming downloadItem is synchronous and returns a promise, simply return the result of calling it, along with a catch to call downloadItemWithRetryAndTimeout recursively.

function wait(n) { return new Promise(resolve => setTimeout(resolve, n)); }

function downloadItemWithRetryAndTimeout(url, retry) {
  if (retry < 0) return Promise.reject();

  return downloadItem(url) . 
    catch(() => wait(1000) . 
      then(() => downloadItemWithRetryAndTimeout(url, retry - 1)
  );
}

Some might find the following slightly cleaner:

function downloadItemWithRetryAndTimeout(url, retry) {
  return function download() {
    return --retry < 0 ? Promise.reject() :
      downloadItem(url) . catch(() => wait(1000) . then(download));
  }();
}