fold

fold<E, A, B>(onErr, onNil, onOk): (outcome) => B

Defined in: Core/Op.ts:674

Eliminates an Outcome with positional handlers. Order: onErr, onNil, onOk — mirrors Result.fold for the first and last cases.

Type Parameters

E

E

A

A

B

B

Parameters

onErr

(e) => B

onNil

() => B

onOk

(a) => B

Returns

(outcome) => B

Example

Op.fold(
  (e) => `error: ${e.message}`,
  ()  => "nothing",
  (v) => `value: ${v}`,
)(outcome);