How should errors be handled with Promises vs async/await?

Short Interview Answer

Use `.catch` / trailing rejection handlers on chains; use try/catch around `await`. Always ensure rejections are handled to avoid unhandledrejection.

Detailed Explanation

Rejected promises propagate down the chain until caught. Mixing styles is fine: `await` turns rejections into exceptions. `try/catch` does not catch errors inside a floating promise without await. `.finally` runs on settle for cleanup but does not absorb errors unless it throws/rejects. In browsers/Node, unhandled rejections emit events and may crash Node depending on version/settings. Prefer catching at meaningful boundaries and rethrowing with context.

Example

async function load() {
  try {
    return await fetch('/x').then((r) => r.json());
  } catch (err) {
    console.error('load failed', err);
    throw err;
  }
}

Interview Tip

Mention `unhandledrejection` — practical ops angle.

Common Mistake

Empty catch blocks that swallow failures silently.