diff --git a/Taskfile.yaml b/Taskfile.yaml
index b7531b9..c0dbd7b 100644
--- a/Taskfile.yaml
+++ b/Taskfile.yaml
@@ -22,10 +22,22 @@ tasks:
             - npx prettier --write {{.CLI_ARGS | default "." }}
             - npx eslint --fix --quiet {{.CLI_ARGS | default "." }}
 
+    lint:delta:
+        cmds:
+          - task: 'lint:prettier:delta'
+          - task: 'lint:eslint:delta'
+
+    lint:prettier:delta:
+        vars:
+            FILES:
+                sh: git diff-ls --diff-filter=d {{.ROOT_BRANCH | default "main"}} | grep -v .vitebook
+        cmds:
+          - npx prettier --check {{.FILES | catLines }}
+
     lint:eslint:delta:
         vars:
             FILES:
-                sh: git diff-ls --diff-filter=d main | grep -v .vitebook
+                sh: git diff-ls --diff-filter=d {{.ROOT_BRANCH | default "main"}} | grep -v .vitebook
         cmds:
             - npx eslint --format=unix {{.FILES | catLines }}
 
diff --git a/docs/tutorial-subduxes.test.js b/docs/tutorial-subduxes.test.js
new file mode 100644
index 0000000..fcb5301
--- /dev/null
+++ b/docs/tutorial-subduxes.test.js
@@ -0,0 +1,91 @@
+import { test, expect } from 'vitest';
+
+import u from 'updeep';
+import R from 'remeda';
+
+import { Updux } from '../src/index.js';
+
+const nextIdDux = new Updux({
+    initial: 1,
+    actions: {
+        incrementNextId: null,
+    },
+    selectors: {
+        getNextId: state => state
+    },
+    mutations: {
+        incrementNextId: () => state => state + 1,
+    }
+});
+
+const matches = conditions => target => Object.entries(conditions).every(
+    ([key,value]) => typeof value === 'function' ? value(target[key]) : target[key] === value
+);
+
+const todoDux = new Updux({
+    initial: {
+        id: 0,
+        description: "",
+        done: false,
+    },
+    actions: {
+        todoDone: null,
+    },
+    mutations: {
+        todoDone: id => u.if( matches({id}), { done: true })
+    },
+    selectors: {
+        desc: R.prop('description'),
+    }
+});
+
+const todosDux = new Updux({
+    initial: [],
+    subduxes: {
+       '*': todoDux
+    },
+    actions: {
+        addTodoWithId: (description, id) => ({description, id} )
+    },
+    findSelectors: {
+        getTodoById: state => id => state.find(matches({id}))
+    },
+    mutations: {
+        addTodoWithId: todo => todos => [...todos, todo]
+    }
+});
+
+const mainDux = new Updux({
+    subduxes: {
+        nextId: nextIdDux,
+        todos: todosDux,
+    },
+    actions: {
+        addTodo: null
+    },
+    effects: {
+        addTodo: ({ getState, dispatch }) => next => action => {
+            const id = getState.getNextId();
+
+            dispatch.incrementNextId()
+
+            next(action);
+
+            dispatch.addTodoWithId( action.payload, id );
+        }
+    }
+});
+
+const store = mainDux.createStore();
+
+
+test( "basic tests", () => {
+
+    const myDesc = 'do the thing';
+    store.dispatch.addTodo(myDesc);
+
+    expect( store.getState.getTodoById(1).desc() ).toEqual(myDesc);
+
+
+
+});
diff --git a/docs/tutorial.md b/docs/tutorial.md
index 22184c0..6626941 100644
--- a/docs/tutorial.md
+++ b/docs/tutorial.md
@@ -170,5 +170,187 @@ console.log(
 );
 ```
 
+## Subduxes
+
+Now that we have all the building blocks, we can embark on the last and
+funkiest part of Updux: its recursive nature.
+
+### Recap: the Todos dux, undivided
+
+Upduxes can be divided into sub-upduxes that deal with the various parts of
+the global state. This is better understood by working out an example, so
+let's recap on the Todos dux we have so far:
+
+```js
+import Updux from 'updux';
+import u from 'updeep';
+import fp from 'lodash/fp';
+
+const todosDux = new Updux({
+    initial: {
+        nextId: 1,
+        todos: [],
+    },
+    actions: {
+        addTodo: null,
+        addTodoWithId: (description, id) => ({description, id, done: false}),
+        todoDone: null,
+        incNextId: null,
+    },
+    selectors: {
+        getTodoById: ({todos}) => id => fp.find({id},todos)
+    },
+    mutations: {
+        addTodoWithId: todo =>
+            u.updateIn( 'todos', todos => [ ...todos, todo] ),
+        incrementNextId: () => u({ nextId: fp.add(1) }),
+        todoDone: (id) => u.updateIn('todos', 
+            u.map( u.if( fp.matches({id}), todo => u({done: true}, todo) ) )
+        ),
+    },
+    effects: {
+        addTodo: ({ getState, dispatch }) => next => action => {
+            const { nextId: id } = getState();
+
+            dispatch.incNextId();
+
+            next(action);
+
+            dispatch.addTodoWithId(action.payload, id);
+        }
+    }
+});
+
+```
+
+This store has two main components: the `nextId`, and the `todos` collection.
+The `todos` collection is itself composed of the individual `todo`s. Let's
+create upduxes for each of those.
+
+### NextId dux
+
+```
+// dux/nextId.js
+
+import { Updux } from 'updux';
+import u from 'updeep';
+
+export default new Updux({
+    initial: 1,
+    actions: {
+        incrementNextId: null,
+    },
+    selectors: {
+        getNextId: state => state
+    },
+    mutations: {
+        incrementNextId: () => state => state + 1,
+    }
+});
+
+```
+
+### Todo updux
+
+```
+// dux/todos/todo/index.ts
+
+import { Updux } from 'updux';
+import u from 'updeep';
+import fp from 'lodash/fp';
+
+export default new Updux({
+    initial: {
+        id: 0,
+        description: "",
+        done: false,
+    },
+    actions: {
+        todoDone: null,
+    },
+    mutations: {
+        todoDone: id => u.if( fp.matches({id}), { done: true }) )
+    },
+    selectors: {
+        desc: ({description}) => description,
+    }
+});
+
+```
+
+### Todos updux
+
+```
+// dux/todos/index.js
+
+import { Updux } from 'updux';
+import u from 'updeep';
+import fp from 'lodash/fp';
+
+import todo from './todo/index.js';
+
+export default new Updux({
+    initial: [],
+    subduxes: {
+       '*': todoDux
+    },
+    actions: {
+        addTodoWithId: (description, id) => ({description, id} )
+    },
+    findSelectors: {
+        getTodoById: state => id => fp.find({id},state)
+    },
+    mutations: {
+        addTodoWithId: todo =>
+            todos => [ ...todos, todo ]
+    }
+});
+```
+
+Note the special '\*' subdux key used here. This
+allows the updux to map every item present in its
+state to a `todo` updux. See [this recipe](/recipes?id=mapping-a-mutation-to-all-values-of-a-state) for details.
+
+### Main store
+
+```
+// dux/index.js
+
+import Updux from 'updux';
+
+import todos from './todos';
+import nextId from './next_id';
+
+export new Updux({
+    subduxes: {
+        nextId,
+        todos,
+    },
+    actions: {
+        addTodo: null
+    },
+    effects: {
+        addTodo: ({ getState, dispatch }) => next => action => {
+            const id = getState.getNextId();
+
+            dispatch.incrementNextId()
+
+            next(action);
+
+            dispatch.addTodoWithId( action.payload, id );
+        }
+    }
+});
+
+```
+
+Tadah! We had to define the `addTodo` effect at the top level as it needs to
+access the `getNextId` selector from `nextId` and the `addTodoWithId`
+action from the `todos`.
+
+Note that the `getNextId` selector still gets the
+right value; when aggregating subduxes selectors Updux auto-wraps them to
+access the right slice of the top object. ```
+
 
 
diff --git a/src/Updux.original b/src/Updux.original
new file mode 100644
index 0000000..586b803
--- /dev/null
+++ b/src/Updux.original
@@ -0,0 +1,457 @@
+/* TODO change * for leftovers to +, change subscriptions to reactions */
+import moize from 'moize';
+import u from 'updeep';
+import { createStore as reduxCreateStore, applyMiddleware } from 'redux';
+import { get, map, mapValues, merge, difference } from 'lodash-es';
+
+import { buildInitial } from './buildInitial/index.js';
+import { buildActions } from './buildActions/index.js';
+import { buildSelectors } from './buildSelectors/index.js';
+import { action } from './actions.js';
+import { buildUpreducer } from './buildUpreducer.js';
+import {
+    buildMiddleware,
+    augmentMiddlewareApi,
+    effectToMiddleware,
+} from './buildMiddleware/index.js';
+
+import {
+    AggregateDuxActions,
+    AggregateDuxState,
+    Dict,
+    ItemsOf,
+    Reducer,
+    Upreducer,
+} from './types.js';
+
+type Mutation<TState,TAction extends { payload?: any }> = (payload:TAction['payload'], action:TAction) => (state: TState) => TState;
+
+/**
+ * Configuration object typically passed to the constructor of the class Updux.
+ */
+export interface UpduxConfig<
+    TState = any,
+    TActions = {},
+    TSelectors = {},
+    TSubduxes = {}
+> {
+    /**
+     * Local initial state.
+     * @default {}
+     */
+    initial?: TState;
+
+    /**
+     * Subduxes to be merged to this dux.
+     */
+    subduxes?: TSubduxes;
+
+    /**
+     * Local actions.
+     */
+    actions?: TActions;
+
+    /**
+     * Local selectors.
+     */
+    selectors?: Record<string, Function>;
+
+    /**
+     * Local mutations
+     */
+    mutations?: Record<string, Function>;
+
+    /**
+     *  Selectors to apply to the mapped subduxes. Only
+     *  applicable if the dux is a mapping dux.
+     */
+    mappedSelectors?: Record<string, Function>;
+
+    /**
+     * Local effects.
+     */
+    effects?: Record<string, Function>;
+
+    /**
+     * Local reactions.
+     */
+    reactions?: Function[];
+
+    /**
+     * If true, enables mapped reactions. Additionally, it can be
+     * a reaction function, which will treated as a regular
+     * reaction for the mapped dux.
+     */
+    mappedReaction?: Function | boolean;
+
+    /**
+     * Wrapping function for the upreducer to provides full customization.
+     * @example
+     * // if an action has the 'dontDoIt' meta flag, don't do anything
+     * const dux = new Updux({
+     *    ...,
+     *    upreducerWrapper: (upreducer) => action => {
+     *        if( action?.meta?.dontDoIt ) return state => state;
+     *        return upreducer(action);
+     *    }
+     * })
+     */
+    upreducerWrapper?: (
+        upreducer: Upreducer<
+            AggregateDuxState<TState, TSubduxes>,
+            ItemsOf<AggregateDuxActions<TActions, TSubduxes>>
+        >
+    ) => Upreducer<
+        AggregateDuxState<TState, TSubduxes>,
+        ItemsOf<AggregateDuxActions<TActions, TSubduxes>>
+    >;
+
+    middlewareWrapper?: Function;
+}
+
+export class Updux<
+    TState extends any = {},
+    TActions extends object = {},
+    TSelectors = {},
+    TSubduxes extends object = {}
+> {
+    /** @type { unknown } */
+    #initial = {};
+    #subduxes = {};
+
+    /** @type Record<string,Function> */
+    #actions = {};
+    #selectors = {};
+    #mutations = {};
+    #effects = [];
+    #reactions = [];
+    #mappedSelectors = undefined;
+    #mappedReaction = undefined;
+    #upreducerWrapper = undefined;
+
+    #middlewareWrapper = undefined;
+
+    constructor(
+        config: UpduxConfig<TState, TActions, TSelectors, TSubduxes>
+    ) {
+        this.#initial = config.initial ?? {};
+        this.#subduxes = config.subduxes ?? {};
+
+        if (config.subduxes) {
+            this.#subduxes = mapValues(config.subduxes, (sub) =>
+                sub instanceof Updux ? sub : new Updux(sub)
+            );
+        }
+
+        if (config.actions) {
+            for (const [type, actionArg] of Object.entries(config.actions)) {
+                if (typeof actionArg === 'function' && actionArg.type) {
+                    this.#actions[type] = actionArg;
+                } else {
+                    const args = Array.isArray(actionArg)
+                        ? actionArg
+                        : [actionArg];
+                    this.#actions[type] = action(type, ...args);
+                }
+            }
+        }
+
+        this.#selectors = config.selectors ?? {};
+        this.#mappedSelectors = config.mappedSelectors;
+
+        this.#mutations = config.mutations ?? {};
+
+        Object.keys(this.#mutations)
+            .filter((action) => action !== '+')
+            .filter((action) => !this.actions.hasOwnProperty(action))
+            .forEach((action) => {
+                throw new Error(`action '${action}' is not defined`);
+            });
+
+        if (config.effects) {
+            this.#effects = Object.entries(config.effects);
+        }
+
+        this.#reactions = config.reactions ?? [];
+
+        this.#mappedReaction = config.mappedReaction;
+
+        this.#upreducerWrapper = config.upreducerWrapper;
+
+        this.#middlewareWrapper = config.middlewareWrapper;
+    }
+
+    #memoInitial = moize(buildInitial);
+    #memoActions = moize(buildActions);
+    #memoSelectors = moize(buildSelectors);
+    #memoUpreducer = moize(buildUpreducer);
+    #memoMiddleware = moize(buildMiddleware);
+
+    setMappedSelector(name, f) {
+        this.#mappedSelectors = {
+            ...this.#mappedSelectors,
+            [name]: f,
+        };
+    }
+
+    get middleware() {
+        return this.#memoMiddleware(
+            this.#effects,
+            this.actions,
+            this.selectors,
+            this.#subduxes,
+            this.#middlewareWrapper,
+            this
+        );
+    }
+
+    setMiddlewareWrapper(wrapper: Function) {
+        this.#middlewareWrapper = wrapper;
+    }
+
+    /** @member { unknown } */
+    get initial(): AggregateDuxState<TState, TSubduxes> {
+        return this.#memoInitial(this.#initial, this.#subduxes);
+    }
+
+    get actions(): AggregateDuxActions<TActions, TSubduxes> {
+        return this.#memoActions(this.#actions, this.#subduxes) as any;
+    }
+
+    get selectors() {
+        return this.#memoSelectors(
+            this.#selectors,
+            this.#mappedSelectors,
+            this.#subduxes
+        );
+    }
+
+    get subduxes() { return this.#subduxes }
+
+    get upreducer(): Upreducer<
+        AggregateDuxState<TState, TSubduxes>,
+        ItemsOf<AggregateDuxActions<TActions, TSubduxes>>
+    > {
+        return this.#memoUpreducer(
+            this.initial,
+            this.#mutations,
+            this.#subduxes,
+            this.#upreducerWrapper
+        );
+    }
+
+    get reducer(): Reducer<
+        AggregateDuxState<TState, TSubduxes>,
+        ItemsOf<AggregateDuxActions<TActions, TSubduxes>>
+    > {
+        return (state, action) => this.upreducer(action)(state);
+    }
+
+    addSubscription(subscription) {
+        this.#reactions = [...this.#reactions, subscription];
+    }
+
+    addReaction(reaction) {
+        this.#reactions = [...this.#reactions, reaction];
+    }
+
+
+    setAction(type, payloadFunc?: (...args: any) => any) {
+        const theAction = action(type, payloadFunc);
+
+        this.#actions = { ...this.#actions, [type]: theAction };
+
+        return theAction;
+    }
+
+    setSelector(name, func) {
+        // TODO selector already exists? Complain!
+        this.#selectors = {
+            ...this.#selectors,
+            [name]: func,
+        };
+        return func;
+    }
+
+    setMutation<TAction extends keyof AggregateDuxActions<TActions,TSubduxes>>(name: TAction, mutation: Mutation<AggregateDuxState<TState, TSubduxes>,
+        ReturnType<AggregateDuxActions<TActions,TSubduxes>[TAction]>>) {
+        if (typeof name === 'function') name = name.type;
+
+        this.#mutations = {
+            ...this.#mutations,
+            [name]: mutation,
+        };
+
+        return mutation;
+    }
+
+    addEffect<TType, E>(action: TType, effect: E): E {
+        this.#effects = [...this.#effects, [action, effect]];
+        return effect;
+    }
+
+    augmentMiddlewareApi(api) {
+        return augmentMiddlewareApi(api, this.actions, this.selectors);
+    }
+
+    splatSubscriber(store, inner, splatReaction) {
+        const cache = {};
+
+        return () => (state, previous, unsub) => {
+            const cacheKeys = Object.keys(cache);
+
+            const newKeys = difference(Object.keys(state), cacheKeys);
+
+            for (const slice of newKeys) {
+                let localStore = {
+                    ...store,
+                    getState: () => store.getState()[slice],
+                };
+
+                cache[slice] = [];
+
+                if (typeof splatReaction === 'function') {
+                    localStore = {
+                        ...localStore,
+                        ...splatReaction(localStore, slice),
+                    };
+                }
+
+                const { unsub, subscriber, subscriberRaw } =
+                    inner.subscribeAll(localStore);
+
+                cache[slice].push({ unsub, subscriber, subscriberRaw });
+                subscriber();
+            }
+
+            const deletedKeys = difference(cacheKeys, Object.keys(state));
+
+            for (const deleted of deletedKeys) {
+                for (const inner of cache[deleted]) {
+                    inner.subscriber();
+                    inner.unsub();
+                }
+                delete cache[deleted];
+            }
+        };
+    }
+
+    subscribeTo(store, subscription, setupArgs = []) {
+        const localStore = augmentMiddlewareApi(
+            {
+                ...store,
+                subscribe: (subscriber) =>
+                    this.subscribeTo(store, () => subscriber),
+            },
+            this.actions,
+            this.selectors
+        );
+
+        const subscriber = subscription(localStore, ...setupArgs);
+
+        let previous;
+
+        const memoSub = () => {
+            const state = store.getState();
+            if (state === previous) return;
+            let p = previous;
+            previous = state;
+            subscriber(state, p, unsub);
+        };
+
+        let ret = store.subscribe(memoSub);
+        const unsub = typeof ret === 'function' ? ret : ret.unsub;
+        return {
+            unsub,
+            subscriber: memoSub,
+            subscriberRaw: subscriber,
+        };
+    }
+
+    subscribeAll(store) {
+        let results = this.#reactions.map((sub) =>
+            this.subscribeTo(store, sub)
+        );
+
+        for (const subdux in this.#subduxes) {
+            if (subdux !== '*') {
+                const localStore = {
+                    ...store,
+                    getState: () => get(store.getState(), subdux),
+                };
+                results.push(this.#subduxes[subdux].subscribeAll(localStore));
+            }
+        }
+
+        if (this.#mappedReaction) {
+            results.push(
+                this.subscribeTo(
+                    store,
+                    this.splatSubscriber(
+                        store,
+                        this.#subduxes['*'],
+                        this.#mappedReaction
+                    )
+                )
+            );
+        }
+
+        return {
+            unsub: () => results.forEach(({ unsub }) => unsub()),
+            subscriber: () =>
+                results.forEach(({ subscriber }) => subscriber()),
+            subscriberRaw: (...args) =>
+                results.forEach(({ subscriberRaw }) =>
+                    subscriberRaw(...args)
+                ),
+        };
+    }
+
+    createStore(initial?: unknown, enhancerGenerator?: Function) {
+        const enhancer = (enhancerGenerator ?? applyMiddleware)(
+            this.middleware
+        );
+
+        const store: {
+            getState: Function & Record<string, Function>;
+            dispatch: Function & Record<string, Function>;
+            selectors: Record<string, Function>;
+            actions: AggregateDuxActions<TActions, TSubduxes>;
+        } = reduxCreateStore(
+            this.reducer as any,
+            initial ?? this.initial,
+            enhancer
+        ) as any;
+
+        store.actions = this.actions;
+
+        store.selectors = this.selectors;
+
+        merge(
+            store.getState,
+            mapValues(this.selectors, (selector) => {
+                return (...args) => {
+                    let result = selector(store.getState());
+
+                    if (typeof result === 'function') return result(...args);
+
+                    return result;
+                };
+            })
+        );
+
+        for (const action in this.actions) {
+            store.dispatch[action] = (...args) => {
+                return store.dispatch(this.actions[action](...(args as any)));
+            };
+        }
+
+        this.subscribeAll(store);
+
+        return store;
+    }
+
+    effectToMiddleware(effect) {
+        return effectToMiddleware(effect, this.actions, this.selectors);
+    }
+}