True Myth / maybe / unwrapOrElse
Function: unwrapOrElse()
Call Signature
unwrapOrElse<
T,U>(orElseFn,maybe):T|U
Safely get the value out of a Maybe by returning the wrapped value if it is Just, or by applying orElseFn if it is Nothing.
This is useful when you need to generate a value (e.g. by using current values in the environment – whether preloaded or by local closure) instead of having a single default value available (as in unwrapOr).
import Maybe from 'true-myth/maybe';
// You can imagine that someOtherValue might be dynamic.
const someOtherValue = 99;
const handleNothing = () => someOtherValue;
const aJust = Maybe.just(42);
console.log(Maybe.unwrapOrElse(handleNothing, aJust)); // 42
const aNothing = nothing<number>();
console.log(Maybe.unwrapOrElse(handleNothing, aNothing)); // 99Type Parameters
T
T
The wrapped value.
U
U
Parameters
orElseFn
() => U
A function used to generate a valid value if maybe is a Nothing.
maybe
Maybe<T>
The Maybe instance to unwrap if it is a Just
Returns
T | U
Either the content of maybe or the value returned from orElseFn.
Call Signature
unwrapOrElse<
T,U>(orElseFn): (maybe) =>T|U
Safely get the value out of a Maybe by returning the wrapped value if it is Just, or by applying orElseFn if it is Nothing.
This is useful when you need to generate a value (e.g. by using current values in the environment – whether preloaded or by local closure) instead of having a single default value available (as in unwrapOr).
import Maybe from 'true-myth/maybe';
// You can imagine that someOtherValue might be dynamic.
const someOtherValue = 99;
const handleNothing = () => someOtherValue;
const aJust = Maybe.just(42);
console.log(Maybe.unwrapOrElse(handleNothing, aJust)); // 42
const aNothing = nothing<number>();
console.log(Maybe.unwrapOrElse(handleNothing, aNothing)); // 99Type Parameters
T
T
The wrapped value.
U
U
Parameters
orElseFn
() => U
A function used to generate a valid value if maybe is a Nothing.
Returns
Either the content of maybe or the value returned from orElseFn.
(
maybe):T|U
Parameters
maybe
Maybe<T>
Returns
T | U