Merge branch 'filtered-effect'

src/Updux.ts

@@ -59,7 +59,7 @@ type ResolveActions<
         [ActionType in keyof A]: ActionType extends string
         ? ResolveAction<ActionType, A[ActionType]>
         : never;
-};
+    };
 
 type Reaction<S = any, M extends MiddlewareAPI = MiddlewareAPI> = (
     api: M,
@@ -311,8 +311,36 @@ export default class Updux<
         this.#defaultMutation = { mutation, terminal };
     }
 
-    addEffect(effect: EffectMiddleware) {
+    addEffect(actionCreator:
+        AggregateActions<ResolveActions<T_LocalActions>, T_Subduxes>,
+        effect: EffectMiddleware): EffectMiddleware;
+    addEffect(guardFunc: (action:
+        AggregateActions<ResolveActions<T_LocalActions>, T_Subduxes>[keyof AggregateActions<ResolveActions<T_LocalActions>, T_Subduxes>]) => boolean,
+        effect: EffectMiddleware): EffectMiddleware;
+    addEffect(effect: EffectMiddleware): EffectMiddleware;
+    addEffect(...args) {
+        let effect;
+        if (args.length === 1) {
+            effect = args[0];
+        }
+        else {
+            const [actionCreator, originalEffect] = args;
+
+            const test = actionCreator.hasOwnProperty('match') ?
+                actionCreator.match : actionCreator;
+
+            effect = (api) => next => {
+                const e = originalEffect(api)(next);
+                return action => {
+                    const func = test(action) ? e : next;
+                    return func(action);
+                }
+            }
+        }
+
         this.#localEffects.push(effect);
+
+        return effect;
     }
 
     get effectsMiddleware() {

src/effects.test.ts

@@ -106,5 +106,57 @@ test('subdux', () => {
     expect(seen).toEqual(1);
 });
 
+test('addEffect with actionCreator', () => {
+    const dux = new Updux({
+        actions: {
+            foo: null,
+            bar: null,
+        },
+    });
+
+    const next = vi.fn();
+    const spy = vi.fn();
+
+    const mw = dux.addEffect(
+        dux.actions.foo,
+        (api) => (next) => (action) => next(spy(action)),
+    );
+
+    mw({})(next)(dux.actions.bar());
+    expect(next).toHaveBeenCalled();
+    expect(spy).not.toHaveBeenCalled();
+
+    next.mockReset();
+    mw({})(next)(dux.actions.foo());
+    expect(next).toHaveBeenCalled();
+    expect(spy).toHaveBeenCalled();
+});
+
+test('addEffect with function', () => {
+    const dux = new Updux({
+        actions: {
+            foo: () => {},
+            bar: () => {},
+        },
+    });
+
+    const next = vi.fn();
+    const spy = vi.fn();
+
+    const mw = dux.addEffect(
+        (action) => action.type[0] === 'f',
+        (api) => (next) => (action) => next(spy(action)),
+    );
+
+    mw({})(next)(dux.actions.bar());
+    expect(next).toHaveBeenCalled();
+    expect(spy).not.toHaveBeenCalled();
+
+    next.mockReset();
+    mw({})(next)(dux.actions.foo());
+    expect(next).toHaveBeenCalled();
+    expect(spy).toHaveBeenCalled();
+});
+
 // TODO subdux effects
 // TODO allow to subscribe / unsubscribe effects?