Sometimes I am confused with 'liftA2' and 'converge' functions.
Main difference between those is that:
liftA2 takes applicative functor as second and third arguements, for example, array
converge takes functions as second and third arguements
// 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
};
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