basic selector mechanism

src/Updux.js

@@ -1,6 +1,7 @@
 import R from 'remeda';
 import { createStore as reduxCreateStore } from 'redux';
 
+import { buildSelectors } from './selectors.js';
 import { action } from './actions.js';
 
 function isActionGen(action) {
@@ -19,6 +20,7 @@ export class Updux {
     #actions;
     #mutations = {};
     #config = {};
+    #selectors = {};
 
     constructor(config = {}) {
         this.#config = config;
@@ -31,6 +33,8 @@ export class Updux {
         Object.entries(this.#subduxes).forEach(([slice, sub]) =>
             this.#addSubduxActions(slice, sub),
         );
+
+        this.#selectors = buildSelectors( config.selectors, config.splatSelectors, this.#subduxes );
     }
 
     #addSubduxActions(_slice, subdux) {
@@ -46,6 +50,10 @@ export class Updux {
         });
     }
 
+    get selectors() {
+        return this.#selectors;
+    }
+
     get actions() {
         return this.#actions;
     }
@@ -119,3 +127,5 @@ export class Updux {
         return store;
     }
 }
+
+export const dux = (config) => new Updux(config);

src/createStore.test.js

@@ -13,7 +13,5 @@ test('basic createStore', async () => {
 
     expect(store.getState()).toEqual({ a: 1 });
 
-    console.log(store.actions.a1);
-
     expect(store.actions.a1).toBeTypeOf('function');
 });

src/dux-selectors.test.js

@@ -0,0 +1,26 @@
+import { test, expect } from 'vitest';
+
+import { dux } from './Updux.js';
+
+test( "basic selectors", () => {
+
+    const foo = dux({
+        initial: {
+            x: 1,
+        },
+        selectors: {
+            getX: ({x}) => x,
+        },
+        subduxes: {
+            bar: {
+                initial: { y: 2 },
+                selectors: {
+                    getY: ({y}) => y
+                }
+            }
+        }
+    });
+
+    expect( foo.selectors.getY({bar:{y:3}} ) ).toBe(3);
+
+} );

src/selectors.js

@@ -0,0 +1,37 @@
+import R from 'remeda';
+
+export function buildSelectors(
+    localSelectors,
+    splatSelector = {},
+    subduxes = {}
+) {
+    const subSelectors = Object.entries(subduxes).map(([slice,{ selectors }]) => {
+        if (!selectors) return {};
+        if (slice === '*') return {};
+
+        return R.mapValues(
+            selectors,
+            (func) => (state) => func(state[slice])
+        );
+    });
+
+    let splat = {};
+
+    for (const name in splatSelector) {
+        splat[name] =
+            (state) =>
+            (...args) => {
+                const value = splatSelector[name](state)(...args);
+
+                const res = () => value;
+                return merge(
+                    res,
+                    mapValues(
+                        subduxes['*'].selectors,
+                        (selector) => () => selector(value)
+                    )
+                );
+            };
+    }
+    return R.mergeAll([ ...subSelectors, localSelectors, splat ]);
+}