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pipelined

fold

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

Defined in: Core/Op.ts:590

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

Type Parameters

Section titled “Type Parameters”

E

Section titled “E”

E

A

Section titled “A”

A

B

Section titled “B”

B

Parameters

Section titled “Parameters”

onErr

Section titled “onErr”

(e) => B

onOk

Section titled “onOk”

(a) => B

onNil

Section titled “onNil”

() => B

Returns

Section titled “Returns”

(outcome): B

Parameters

Section titled “Parameters”

outcome

Section titled “outcome”

Outcome<E, A>

Returns

Section titled “Returns”

B

Example

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