maybe-adapter

The maybe-adapter package provides functions to convert to/from Maybe types.

Functions

toResult

This function has a curried and non-curried form. It takes an error and a Maybe. When the Maybe is a Just, a successful Result is returned with the wrapped value, otherwise an error Result is returned with the given error value.

import { toResult } from '@execonline-inc/maybe-adapter';
import { nothing } from 'maybeasy';

toResult<string, number>('an error message')(nothing());

toTask

This function has a curried and non-curried form. It takes an error and a Maybe. When the Maybe is a Just, a succeeding Task is returned with the wrapped value, otherwise a failing Task is returned with the given error value.

import { toTask } from '@execonline-inc/maybe-adapter';
import { nothing } from 'maybeasy';

toTask<string, number>('an error message')(nothing());

fromBool, when

This function has a curried and non-curried form. It wraps a given value in a Maybe depending on either the given boolean value or boolean return value of the given function.

Also, if the first argument is a function, the second argument is passed to that function for evaluation. (See advanced usage example)

Aliased as when

import { fromBool } from '@execonline-inc/maybe-adapter';

fromBool(true)(123);
fromBool((): boolean => true)(123);
// Just<123>

// Advanced usage.
mapMaybe(when(even), [1, 2, 3, 4]);
// [2, 4]