API reference › @evolu/common › Type › undefinedOr

function undefinedOr<T>(
  type: T,
): UnionType<
  [
    Type<
      "Undefined",
      undefined,
      undefined,
      UndefinedError,
      undefined,
      UndefinedError
    >,
    T,
  ]
>;

Defined in: packages/common/src/Type.ts:3886

union(undefined, T) Type.

Example

const UndefinedOrString = undefinedOr(String);
UndefinedOrString.from("world"); // ok("world")
UndefinedOrString.from(undefined); // ok()
UndefinedOrString.from(42); // err(...)
Markdown for LLMs