Kif taħdem għall-iżbalji fil-JavaScript, inklużi koodu async?

Question

Accepted Answer

Il-ġbalfn sinkroni jużaw **`try/catch/finally`**, u għandek titfa' `Error` oġġetti (mhux strinzi) sabiex tikseb stack trace.

```js
try {
  const data = JSON.parse(input);
} catch (err) {
  if (err instanceof SyntaxError) handleBadJson(err);
  else throw err;        // re-throw what you can't handle
} finally {
  cleanup();             // always runs
}
```

## Il-ġestjoni tal-iżbalji async hija differenti skont l-istil

```js
// async/await → wrap awaits in try/catch
async function load() {
  try {
    return await fetch(url).then(r => r.json());
  } catch (err) { showError(err); }
}

// promises → use .catch
fetch(url).then(use).catch(showError);
```

## Inxieb komuni: try/catch ma jiffundax callbacks async

```js
try {
  setTimeout(() => { throw new Error("boom"); }, 0); // ❌ NOT caught
} catch (e) { /* never runs — the throw happens later, outside this stack */ }
```

Il-callback ta' `setTimeout` taħdem fuq tick aktar tard, għalhekk is-surrounding `try` ġie perdutu ħafna ħin ilu. Iggesti l-iżball *ġewwa* il-callback.

## Xbieki tal-sigurtà globali

```js
window.addEventListener("unhandledrejection", e => log(e.reason)); // browser
process.on("unhandledRejection", err => log(err));                 // Node
```

## Aħjar prattiki

- Itfa' `Error` (jew subclasses personalizzati) għal stack traces u kontrolli ta' `instanceof`.
- Aqbad **speċifikament* fejn tista' tirekkupera; ħalli l-iżbalji inaspettati jixperu barra.
- Qatt tqammu ma torbotu l-iżbalji (`catch (e) {}`). Dejjem log jew rethrow.