Errors and nulls

Required

• Throw exceptions instead of returning error codes

  Required

  Signal failure with an exception or a typed result. Never return a magic value such as -1, false or an error string that callers must remember to check.

• Never return null

  Required

  Collections return empty, services use a Null Object, and lookups return one consistent "absent" value. A caller should never crash because it forgot a check.

• Never pass null into a function

  Required

  Never call a function with null to mean "use the default" or "skip this". Give the function a clear variant or an options object instead.

• Make fields required unless absence is real

  Required

  Every constructor argument and data object field is required and non-nullable, unless "not there" is a real state of the business.

• Never swallow errors

  Required

  Never catch an error and carry on as if nothing happened. Handle it, add context and rethrow it, or let it reach the edge.

• Await every async call

  Required

  Await every promise, task or future, or hand it to code that handles its errors. A call that nobody waits for loses its errors without a trace.

Recommended

• Use typed domain exceptions

  Recommended

  Give each kind of failure its own exception type with a clear name and the data needed to handle it. Never throw a bare generic error with only a message.