updux/src/initialState.ts

import u from '@yanick/updeep-remeda';
import { D } from '@mobily/ts-belt';

export function buildInitialState(localInitialState, subduxes) {
    let state = localInitialState ?? {};

    if (subduxes) {
        if (typeof state !== 'object') {
            throw new Error('root initial state is not an object');
        }

        state = u(state, D.map(subduxes, D.prop('initialState')));
    }

    return state;
}