[Functional Programming] liftA2 and converge

// liftA2 :: applicative m => (a -> b -> C) -> m a -> m b -> m c
// converge :: (b -> c -> d) -> (a -> b) -> (a -> C) -> a -> d

// liftA2 :: applicative m => (a -> b -> C) -> m a -> m b -> m c
// converge :: (b -> c -> d) -> (a -> b) -> (a -> C) -> a -> d
const { option,curry,liftA2,converge } = require("crocks");
const { getState } = require("../../Helper");

// getColors :: () -> State AppState [String]
const getColors = () => getState("colors").map(option([]));

// getShapes :: () -> State AppState [String]
const getShapes = () => getState("shapes").map(option([]));

// buildCard :: String -> String -> Card
const buildCard = curry((color,shapE) => ({
  id: `${Color}-${shapE}`,color,shape
}));

// buildCards :: [String] -> [String] -> [Card]
const buildCards = liftA2(buildCard);

// generateCards :: () -> State AppState [ Card ]
const generateCards = converge(liftA2(buildCards),getColors,getShapes);

module.exports = {
  generateCards
};