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bad-example.com
1import { useCallback } from 'react';
2
3export function asyncThrottle(minT, callback, followUp) {
4 let timer = null;
5 let lastArgs = null;
6
7 let throttleId = 0;
8
9 function throttled(...args) {
10 // always make sure our callback args are fresh
11 lastArgs = args;
12
13 // early exit if we're waiting for the throttle still
14 if (timer !== null) {
15 return;
16 }
17
18 // otherwise we're starting a timer. make sure we know who we are.
19 let myThrottle = ++throttleId;
20 // we immediately get a new timer id
21 timer = setTimeout(async () => {
22 // make sure we synchronously clear this so next throttle isn't lost
23 timer = null;
24 // *then* we can start the actual callback
25 let res = await callback(...lastArgs);
26 // but since we awaited the callback, it's now possible to be stale, so check
27 if (myThrottle === throttleId) {
28 followUp(res);
29 }
30 }, minT);
31
32 }
33 return throttled;
34}