Function: or()
Call Signature
or<
T>(defaultMaybe,maybe):Maybe<T>
Provide a fallback for a given Maybe. Behaves like a logical or: if the maybe value is a Just, returns that maybe; otherwise, returns the defaultMaybe value.
This is useful when you want to make sure that something which takes a Maybe always ends up getting a Just variant, by supplying a default value for the case that you currently have a nothing.
import Maybe from 'true-utils/maybe';
const justA = Maybe.just("a");
const justB = Maybe.just("b");
const aNothing: Maybe<string> = nothing();
console.log(Maybe.or(justB, justA).toString()); // Just(A)
console.log(Maybe.or(aNothing, justA).toString()); // Just(A)
console.log(Maybe.or(justB, aNothing).toString()); // Just(B)
console.log(Maybe.or(aNothing, aNothing).toString()); // NothingType Parameters
T
T
The type of the wrapped value.
Parameters
defaultMaybe
Maybe<T>
The Maybe to use if maybe is a Nothing.
maybe
Maybe<T>
The Maybe instance to evaluate.
Returns
Maybe<T>
maybe if it is a Just, otherwise defaultMaybe.
Call Signature
or<
T>(defaultMaybe): (maybe) =>Maybe<T>
Provide a fallback for a given Maybe. Behaves like a logical or: if the maybe value is a Just, returns that maybe; otherwise, returns the defaultMaybe value.
This is useful when you want to make sure that something which takes a Maybe always ends up getting a Just variant, by supplying a default value for the case that you currently have a nothing.
import Maybe from 'true-utils/maybe';
const justA = Maybe.just("a");
const justB = Maybe.just("b");
const aNothing: Maybe<string> = nothing();
console.log(Maybe.or(justB, justA).toString()); // Just(A)
console.log(Maybe.or(aNothing, justA).toString()); // Just(A)
console.log(Maybe.or(justB, aNothing).toString()); // Just(B)
console.log(Maybe.or(aNothing, aNothing).toString()); // NothingType Parameters
T
T
The type of the wrapped value.
Parameters
defaultMaybe
Maybe<T>
The Maybe to use if maybe is a Nothing.
Returns
maybe if it is a Just, otherwise defaultMaybe.
(
maybe):Maybe<T>
Parameters
maybe
Maybe<T>
Returns
Maybe<T>