add splatReaction support

src/Updux.js

@@ -14,6 +14,7 @@ import { action, isActionGen } from './actions.js';
  */
 
 export class Updux {
+    #name = 'unknown';
     #localInitial = {};
     #subduxes = {};
     #actions;
@@ -23,10 +24,15 @@ export class Updux {
     #effects = [];
     #localReactions = [];
     #middlewareWrapper;
+    #splatReactionMapper;
 
     constructor(config = {}) {
         this.#config = config;
 
+        this.#name = config.name || 'unknown';
+
+        this.#splatReactionMapper = config.splatReactionMapper;
+
         this.#middlewareWrapper = config.middlewareWrapper;
 
         this.#localInitial = config.initial;
@@ -58,6 +64,10 @@ export class Updux {
         this.#localReactions = config.reactions ?? [];
     }
 
+    get name() {
+        return this.#name;
+    }
+
     #addSubduxActions(_slice, subdux) {
         if (!subdux.actions) return;
         // TODO action 'blah' defined multiple times: <where>
@@ -206,16 +216,15 @@ export class Updux {
     }
 
     subscribeTo(store, subscription) {
-        const localStore = this.augmentMiddlewareApi(
-            {
-                ...store,
-                subscribe: (subscriber) => this.subscribeTo(store, subscriber), // TODO not sure
-            }
-        );
+        const localStore = this.augmentMiddlewareApi({
+            ...store,
+            subscribe: (subscriber) => this.subscribeTo(store, subscriber), // TODO not sure
+        });
 
         const subscriber = subscription(localStore);
 
         let previous;
+        let unsub;
 
         const memoSub = () => {
             const state = store.getState();
@@ -225,38 +234,81 @@ export class Updux {
             subscriber(state, p, unsub);
         };
 
-        let ret = store.subscribe(memoSub);
-        const unsub = typeof ret === 'function' ? ret : ret.unsub;
-        return {
-            unsub,
-            subscriberMemoized: memoSub,
-            subscriber,
+        return store.subscribe(memoSub);
+    }
+
+    createSplatReaction() {
+        const subdux = this.#subduxes['*'];
+        const mapper = this.#splatReactionMapper;
+
+        return (api) => {
+            const cache = {};
+
+            return (state, previousState, unsubscribe) => {
+                const gone = { ...cache };
+
+                // TODO assuming object here
+                for (const key in state) {
+                    if (cache[key]) {
+                        delete gone[key];
+                    } else {
+                        const dux = new Updux({
+                            initial: null,
+                            actions: { update: null },
+                            mutations: {
+                                update: (payload) => () => payload,
+                            },
+                        });
+                        const store = dux.createStore();
+                        // TODO need to change the store to have the
+                        // subscribe pointing to the right slice?
+                        const context = {
+                            ...(api.context ?? {}),
+                            [subdux.name]: key,
+                        };
+                        const unsub = subdux.subscribeAll({
+                            ...store,
+                            context,
+                        });
+                        cache[key] = { store, unsub };
+                    }
+                    cache[key].store.dispatch.update(state[key]);
+                }
+
+                for (const key in gone) {
+                    cache[key].store.dispatch.update(null);
+                    cache[key].unsub();
+                    delete cache[key];
+                }
+            };
         };
     }
 
+    subscribeSplatReaction(store) {
+        return this.subscribeTo(store, this.createSplatReaction());
+    }
+
     subscribeAll(store) {
-        let results = this.#localReactions.map((sub) =>
+        let unsubs = this.#localReactions.map((sub) =>
             this.subscribeTo(store, sub),
         );
 
-        for (const subdux in this.#subduxes) {
-            if (subdux !== '*') {
-                const localStore = {
-                    ...store,
-                    getState: () => store.getState()[subdux],
-                };
-                results.push(this.#subduxes[subdux].subscribeAll(localStore));
-            }
+        if (this.#splatReactionMapper) {
+            unsubs.push(this.subscribeSplatReaction(store));
         }
 
-        return {
-            unsub: () => results.forEach(({ unsub }) => unsub()),
-            subscriberMemoized: () =>
-                results.forEach(({ subscriberMemoized }) =>
-                    subscriberMemoized(),
-                ),
-            subscriber: () => results.forEach(({ subscriber }) => subscriber()),
-        };
+        unsubs.push(
+            ...Object.entries(this.#subduxes)
+                .filter(([slice]) => slice !== '*')
+                .map(([slice, subdux]) => {
+                    subdux.subscribeAll({
+                        ...store,
+                        getState: () => store.getState()[slice],
+                    });
+                }),
+        );
+
+        return () => unsubs.forEach((u) => u());
     }
 }
 

src/splatReactions.test.js

@@ -0,0 +1,127 @@
+import { test, expect, vi, describe } from 'vitest';
+import u from 'updeep';
+
+import { Updux } from './Updux.js';
+import { matches } from './utils';
+
+const reactionSnitch = vi.fn();
+const thingReactionSnitch = vi.fn();
+
+const subThing = new Updux({
+    name: 'subThing',
+    initial: 0,
+});
+
+subThing.addReaction((api) => (state, previousState, unsubscribe) => {
+    reactionSnitch({ ...api, state, previousState });
+});
+
+const thing = new Updux({
+    name: 'thing',
+    initial: {},
+    subduxes: {
+        '*': subThing,
+    },
+    actions: {
+        setSubThing: (id, value, thingId) => ({ thingId, id, value }),
+        deleteSubThing: (id) => id,
+    },
+    mutations: {
+        setSubThing: ({ id, value }) => u.updateIn(id, value),
+        deleteSubThing: (id) => u.updateIn(id, u.omitted),
+    },
+    splatReactionMapper: ({ id }) => id,
+});
+
+thing.addReaction((api) => (state, previousState, unsubscribe) => {
+    thingReactionSnitch({ ...api, state, previousState });
+});
+
+const things = new Updux({
+    subduxes: {
+        '*': thing,
+    },
+    initial: {},
+    actions: { newThing: (id) => id },
+    splatReactionMapper: ({ id }) => id,
+    mutations: {
+        newThing: (id) => (state) => ({ ...state, [id]: thing.initial }),
+    },
+});
+
+things.setMutation(
+    'setSubThing',
+    ({ thingId }, action) => u.updateIn(thingId, thing.upreducer(action)),
+    true,
+);
+
+describe('just one level', () => {
+    const store = thing.createStore();
+
+    test('set', async () => {
+        store.dispatch.setSubThing('a', 13);
+
+        expect(reactionSnitch).toHaveBeenCalledWith(
+            expect.objectContaining({ state: 13 }),
+        );
+    });
+
+    test('other key', async () => {
+        reactionSnitch.mockReset();
+
+        store.dispatch.setSubThing('b', 23);
+
+        expect(reactionSnitch).not.toHaveBeenCalledWith(
+            expect.objectContaining({ state: 13 }),
+        );
+        expect(reactionSnitch).toHaveBeenCalledWith(
+            expect.objectContaining({ state: 23 }),
+        );
+    });
+
+    test('delete', async () => {
+        reactionSnitch.mockReset();
+
+        store.dispatch.deleteSubThing('a');
+
+        expect(reactionSnitch).toHaveBeenCalledOnce();
+
+        expect(reactionSnitch).toHaveBeenCalledWith(
+            expect.objectContaining({ state: null }),
+        );
+    });
+
+    test('context', async () => {
+        expect(reactionSnitch).toHaveBeenCalledWith(
+            expect.objectContaining({
+                context: { subThing: 'a' },
+            }),
+        );
+    });
+});
+
+test('two levels', async () => {
+    const store = things.createStore();
+
+    reactionSnitch.mockReset();
+    thingReactionSnitch.mockReset();
+
+    store.dispatch.newThing('alpha');
+    store.dispatch.newThing('beta');
+    store.dispatch.setSubThing('a', 13, 'alpha');
+
+    expect(reactionSnitch).toHaveBeenCalledWith(
+        expect.objectContaining({
+            context: { thing: 'alpha', subThing: 'a' },
+            state: 13,
+        }),
+    );
+    expect(thingReactionSnitch).toHaveBeenCalledWith(
+        expect.objectContaining({
+            context: {
+                thing: 'alpha',
+            },
+            state: { a: 13 },
+        }),
+    );
+});