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Async Errors

Errors in asynchronous operations follow the same propagation rules as synchronous code.

Why this exists​

Asynchronous operations can fail, and their errors need to be handled consistently with the language's error model.

How it works​

Errors thrown in awaited expressions propagate to the awaiting context. Async functions can throw errors that are caught by try/catch blocks around await expressions.

Examples​

fn asyncOperation() {
  await delay(1000)
  throw "Operation failed"
}

try {
  await asyncOperation()
} catch error {
  say "Async operation failed: " + error
}

# Error in promise-like operation
fn fetchData() {
  return await httpGet("api/data")
}

try {
  set data = await fetchData()
} catch error {
  say "Failed to fetch data: " + error
}

Common mistakes​

  • Forgetting that await can throw errors
  • Not wrapping async calls in try/catch
  • Assuming async errors behave differently from sync errors