effects with function

src/Updux.ts

@@ -314,6 +314,9 @@ export default class Updux<
     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;
@@ -323,10 +326,13 @@ export default class Updux<
         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 = actionCreator.match(action) ? e : next;
+                    const func = test(action) ? e : next;
                     return func(action);
                 }
             }

src/effects.test.ts

@@ -39,7 +39,7 @@ test('buildEffectsMiddleware', () => {
 
     expect(seen).toEqual(0);
     const dispatch = vi.fn();
-    mw({ getState: () => 'the state', dispatch })(() => { })({
+    mw({ getState: () => 'the state', dispatch })(() => {})({
         type: 'noop',
     });
     expect(seen).toEqual(1);
@@ -117,8 +117,35 @@ test('addEffect with actionCreator', () => {
     const next = vi.fn();
     const spy = vi.fn();
 
-    const mw = dux.addEffect(dux.actions.foo, (api) => (next) => (action) =>
-        next(spy(action))
+    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());