Awesome

fantasy-derivations

The fantasy-land spec only requires ADTs to define the minimum set of methods necessary for its type. Others can be derived. Fantasyland gives the code necessary for the derivations, but leaves it up to either the implementer or consumer to put them to use. fantasy-derivations allows you to access methods on various ADTs that can support them without worrying whether they are in fact defined.

Example

var fallback = require('fantasy-derivations')
var monad = require('some-monad-library-with-only-chain-defined')

var my_monad = monad.of(0)

fallback('map', my_monad)(function (n) { return n + 1 })
// monad.of(1)

API

The exported function takes a string (a method name) and an ADT and does its best to return a function for that ADT matching spec.