expect

Type-focused helper that returns the same Either while keeping strict Left/Right typing.

Interactive example

Syntax

function expect<
  GenericEither extends Right | Left
>(
  input: GenericEither
): GenericEither;

Parameters

• input: Either value to preserve.

Return value

Returns exactly the same runtime value as input. The function is mainly useful to preserve strict Either typing in composed flows.

See also

• matchInformation - Exhaustive matching by information.
• matchInformationOtherwise - Non-exhaustive matching with fallback.