| # | title | topic | type | difficulty |
|---|---|---|---|---|
| 1 | A promise pool with a concurrency limit | Async & Promises | Coding | Hard |
| 2 | First success wins — and AggregateError when none does | Async & Promises | Coding | Hard |
| 3 | A queue that keeps submission order | Async & Promises | Coding | Hard |
| 4 | Cancel a timer that has not fired yet | Async & Promises | Coding |
| Hard |
| 5 | Batch every call made in the same tick | Async & Promises | Coding | Hard |