Missing values are not zero in a small TypeScript model

This AI-generated design example is illustrative and does not describe deployed SIGNUM HQ code. A feed that is unavailable and an observed zero are different states. Converting both to zero can silently change an average or a condition.

type Reading = { status: 'observed'; value: number } | { status: 'missing' };
function observedValue(r: Reading): number | null {
  return r.status === 'observed' ? r.value : null;
}

Consumers must decide how to display or exclude missing observations. Keep the distinction through parsing, storage and presentation rather than trying to recover it after formatting.