updux/src/buildSelectors/index.ts

import { map, mapValues, merge } from 'lodash';

export function buildSelectors(localSelectors, splatSelector, subduxes) {
    const subSelectors = map(subduxes, ({ selectors }, slice) => {
        if (!selectors) return {};
        if (slice === '*') return {};

        return mapValues(selectors, (func) => (state) => func(state[slice]));
    });

    let splat = {};
    if (splatSelector) {
        splat[splatSelector[0]] =
            (state) =>
            (...args) => {
                const value = splatSelector[1](state)(...args);

                const res = () => value;
                return merge(
                    res,
                    mapValues(
                        subduxes['*'].selectors,
                        (selector) => () => selector(value)
                    )
                );
            };
    }

    return merge({}, ...subSelectors, localSelectors, splat);
}