scoped-kv-idea.js

import { createStore, createEvent, is, fork, allSettled } from 'effector';
import { produce } from 'immer';

function createCollection(store, events) {
    const collection = createStore({});
    const setStoreValue = createEvent();
    store.on(setStoreValue, (state, value) => value);

    let length = 0;
    let keys = [];
    collection.watch((obj) => {
        keys = Object.keys(obj);
        length = Object.keys(obj).length;
    });

    return {
        store: collection,
        get length() {
            return length;
        },
        get keys() {
            return keys;
        },
        add(key, value) {
            const scope = fork();
            allSettled(setStoreValue, { scope, params: value });
            const item = {
                key,
                scope,
                get value() {
                    return scope.getState(store);
                },
                ...Object.keys(events).reduce((acc, name) => {
                    acc[name] = Object.assign(function (params) {
                        allSettled(events[name], { scope, params });
                    }, events[name]);
                    return acc;
                }, {}),
            };
            collection.setState({
                ...collection.getState(),
                [key]: item,
            });

            return item;
        },
    };
}

const setUser = createEvent();
const addRole = createEvent();
const removeRole = createEvent();

const $user = createStore({
    name: 'guest',
    age: -1,
    roles: { admin: false, user: false, guest: true },
});

$user
    .on(setUser, (user, info) => ({ ...user, ...info }))
    .on(
        addRole,
        produce((user, role) => {
            if (['admin', 'user'].includes(role)) {
                user.roles.guest = false;
                user.roles[role] = true;
            } else {
                user.roles.guest = true;
                user.roles.user = false;
                user.roles.admin = false;
            }
        })
    )
    .reset(removeRole);

$user.watch((user) => console.log('user:', user.name, user.age, user.roles));

export const $users = createCollection($user, { setUser, addRole, removeRole });

const user1 = $users.add(1, {
    name: 'guest',
    age: -1,
    roles: { admin: false, user: false, guest: true },
});

const user2 = $users.add(2, {
    name: 'User 1',
    age: 18,
    roles: { admin: false, user: true, guest: false },
});

user1.addRole('admin');
user2.addRole('admin');
user1.removeRole();