/effect-ts

Option and Nullable Boundaries

Use Option<A> for meaningful absence inside Effect domain logic. Use A | null or A | undefined only when the external contract requires it, such as JSON, React state, browser storage, or a third-party API.

Normalize once:

• incoming nullable value: Option.fromNullable at the boundary;
• outgoing JSON or React value: Option.getOrNull or Option.getOrUndefined at the boundary;
• optional Schema domain field: Schema.optionalWith(schema, { as: "Option" });
• explicitly nullable encoded field: Schema.NullOr(schema).

Do not repeatedly wrap an Option with Option.fromNullable; flatten nested options when separate operations each introduce meaningful absence. Database repositories may return Option<A> when no row is normal, then translate Option.none to a tagged domain error at the service boundary when the caller requires existence.