Do not gobble up errors

Don't silently gobble up errors. If an error occurs, ensure it's logged and handled appropriately.

In many cases, letting an error bubble up is better than a try/catch block which incorrectly "handles" the error.

❌Bad:

function getTraceId(request) {
  try {
    return request['trace_id'];
  } catch (e) {
    return null;
  }
}

😱 null is not actually a valid value! Assuming that requests should always have a trace id, this is a fatal error and should be allowed to bubble and crash the request.

✅Good:

function getTraceId(request) {
  try {
    return request['trace_id'];
  } catch (e) {
    throw new Error('Could not find the trace id', { cause: e });
  }
}

✅Also good:

The try/catch above doesn't actually add much. Just let it fail!

function getTraceId(request) {
  return request['trace_id'];
}

Why?

In our example, null is not a sementically valid value, and may cause undefined behaviour and other errors later on in the app.

Catching the error and returning null silently gobbles up the original error. We have no way of knowing this error occured; no error is thrown, no logs are generated.