@markandrus/effect-derive/lib/Recursive.js

Derive Covariant (Functor), Foldable, and Traversable instances, as well as base functors, for algebraic data types (ADTs)

import { extract } from './data/Cofree';
export const cata = (T) => (g) => {
    return function go(t) {
        return g(T.F.map(T.project(t), go));
    };
};
export const para = (T) => (g) => {
    return function go(t) {
        return g(T.F.map(T.project(t), _ => [_, go(_)]));
    };
};
export const histo = (T) => (g) => (ta) => {
    function go(ta) {
        const bc = T.F.map(T.project(ta), go);
        return [g(bc), bc];
    }
    return extract(go(ta));
};