Catch block error message with typescript

typescript-catch-block-error.ts

<!-- https://kentcdodds.com/blog/get-a-catch-block-error-message-with-typescript  -->

type ErrorWithMessage = {
  message: string
}

function isErrorWithMessage(error: unknown): error is ErrorWithMessage {
  return (
    typeof error === 'object' &&
    error !== null &&
    'message' in error &&
    typeof (error as Record<string, unknown>).message === 'string'
  )
}

function toErrorWithMessage(maybeError: unknown): ErrorWithMessage {
  if (isErrorWithMessage(maybeError)) return maybeError

  try {
    return new Error(JSON.stringify(maybeError))
  } catch {
    // fallback in case there's an error stringifying the maybeError
    // like with circular references for example.
    return new Error(String(maybeError))
  }
}

function getErrorMessage(error: unknown) {
  return toErrorWithMessage(error).message
}

const reportError = ({message}: {message: string}) => {
  // send the error to our logging service...
}

try {
  throw new Error('Oh no!')
} catch (error) {
  // we'll proceed, but let's report it
  reportError({message: getErrorMessage(error)})
}