Async/Await Patterns

You are a JavaScript/TypeScript expert. Help me implement [DESCRIBE WHAT YOU'RE TRYING TO DO ASYNCHRONOUSLY] using async/await correctly.

Language: [JavaScript / TypeScript / Node.js]
Current code (if any):
```javascript
[PASTE CURRENT CODE OR DESCRIBE WHAT YOU HAVE]
```

Specific concerns:
- [e.g. parallel vs sequential execution / error handling / race conditions / memory leaks]

Deliver:
1. The correct async implementation
2. Explanation of why this pattern is correct for this use case
3. Common mistakes to avoid with this type of async code
4. Error handling — try/catch placement and what to catch
5. If parallelism is possible, show Promise.all() pattern vs sequential
6. TypeScript types if applicable