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Simplifies testing promise-returning-functions that executes timers (setTimeout / setInterval). The helper `runTimersUntilResolved` will run the timers repeatedly until the promise resolves. Jest helper.
/*
* Run timers (setInterval/setTimeout) every tick continuously until the promise has been resolved
*/
async function runTimersUntilResolved(fn: () => Promise<any>) {
jest.useFakeTimers();
let isResolved = false;
const p = fn();
p.finally(() => (isResolved = true));
while (isResolved === false) {
// tick
await new Promise((resolve) => setImmediate(resolve));
// run timers
jest.runAllTimers();
}
return p;
}
// Example:
const res = await runTimersUntilResolved(() => myAsyncOperation())
expect(rest).toEqual('something');
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