fantasyland extensions for immutablejs
npm install immutable-ext
In addition to the Functor, Foldable, and Monad functions, we now have:
- Monoid
- Applicative (list only right now)
- Traversable
Plus stuff that builds off of reduce like foldMap. Please contribute/complain as you want/need things.
We can now traverse without messing with Array or Object:
const { List, Map } = require('immutable-ext') const Task = require('data.task') const IO = require('fantasy-io') // Given Http.get :: String -> Task Error Blog List.of('/blog/1', '/blog/2') .traverse(Task.of, Http.get) .fork(console.error, console.log) // List(Blog, Blog) Map({home: "<div>homepage</div>", faq: "<p>ask me anything</p>"}) .traverse(IO.of, (v, k) => new IO(v => $('body').append(v))) // IO(Map({home: "[dom]", faq: "[dom]"})
We can fold stuff down
const {Disjunction, Additive} = require('fantasy-monoids') List.of([1,2,3], [4,5,6]).fold([]) //[1,2,3,4,5,6] Map({a: "hidy", b: "hidy", c: "ho"}).fold("") // "hidyhidyho" List.of(Map({a: Additive(1), b: Disjunction(true), c: "son", d: [1], e: 'wut'}), Map({a: Additive(2), b: Disjunction(false), c: "ofa", d: [2]}), Map({a: Additive(3), b: Disjunction(false), c: "gun", d: [3]})).fold(Map.empty), // Map({a: Additive(6), b: Disjunction(true), c: "sonofagun", d: [1,2,3], e: 'wut'})))
foldMap some things
List.of(1,2,3,4).foldMap(Additive, Additive.empty) // Additive(10) Map({a: true, b: false}).foldMap(Disjunction, Disjunction.empty) // Disjunction(true)
We can ap to get us some list comprehensions
List.of(x => y => x + y) .ap(List.of('a', 'b', 'c')) .ap(List.of('+', '-')) // List('a+', 'a-', 'b+', 'b-', 'c+', 'c-')