True Myth / maybe / flatten

Function: flatten()

flatten<T>(nested): Maybe<T>

Given a nested Maybe, remove one layer of nesting.

For example, given a Maybe<Maybe<string>>, the resulting type after using this function will be Maybe<string>.

Note

This function only works when the value wrapped in Maybe is another Maybe. If you have a Maybe<string> or Maybe<number>, this function won't work. If you have a Maybe<Maybe<string>>, then you can call maybe.flatten(theMaybe) to get back a Maybe<string>.

Examples

import * as maybe from 'true-myth/maybe';

const nested = maybe.just(maybe.just('hello'));
const flattened = maybe.flatten(nested); // Maybe<string>
console.log(flattened); // Just('hello')

const nestedNothing = maybe.just(maybe.nothing<string>());
const flattenedNothing = maybe.flatten(nestedNothing); // Maybe<string>
console.log(flattenedNothing); // Nothing

const nothingNested = maybe.nothing<Maybe<string>>();
const flattenedOuter = maybe.flatten(nothingNested); // Maybe<string>
console.log(flattenedOuter); // Nothing

Type Parameters

T

T extends object

Parameters

nested

Maybe<Maybe<T>>

Returns

Maybe<T>