Discriminated union result type for pipeline stages. The ok discriminant guarantees TypeScript can narrow to exactly one branch — ok: true always carries value: T and never error; ok: false always carries error and never value. This prevents impossible states such as { ok: true, error: '…' } and eliminates the need for non-null assertions in well-typed consumers.
Discriminated union result type for pipeline stages. The
okdiscriminant guarantees TypeScript can narrow to exactly one branch —ok: truealways carriesvalue: Tand nevererror;ok: falsealways carrieserrorand nevervalue. This prevents impossible states such as{ ok: true, error: '…' }and eliminates the need for non-null assertions in well-typed consumers.