feat(createAction): add parameter payloadCreator, metaCreators (#12)

index.d.ts

@@ -17,7 +17,7 @@ declare module 'redux-fluent' {
     P extends object = object,
     M extends object = object,
     T extends string = string
-  >(type: T): I.ActionCreator<P, M, T>;
+    >(type: T, payloadCreator?: (p: any) => P, metaCreator?: (m: any) => M): I.ActionCreator<P, M, T>;
 }
 
 declare namespace /* Interfaces */ I {

src/Action/Action.js

@@ -1,11 +1,16 @@
-export default function ActionCreatorFactory(type) {
-  function actionCreator(payload, meta) {
+const identity = arg => arg;
+
+export default function ActionCreatorFactory(type, payloadCreator, metaCreator) {
+  function actionCreator(rawPayload, rawMeta) {
     const action = Object.create(null);
 
+    const payload = (payloadCreator || identity)(rawPayload) || null;
+    const meta = (metaCreator || identity)(rawMeta) || null;
+
     action.type = type;
     action.error = payload instanceof Error;
-    action.meta = meta || null;
-    action.payload = payload || null;
+    action.meta = meta;
+    action.payload = payload;
 
     return Object.freeze(action);
   }

src/Action/Action.spec.js

@@ -9,6 +9,28 @@ describe('createAction', () => {
     expect(createAction('test')).toEqual(jasmine.any(Function));
   });
 
+  it('Factory should accept a payloadCreator', () => {
+    const payloadCreator = jasmine.createSpy('payloadCreator')
+      .and.callFake(todoId => ({ id: todoId }));
+
+    const deleteTodo = createAction('@@todos/:id | delete', payloadCreator);
+    const todoId = 12;
+
+    expect(deleteTodo(todoId).payload).toEqual({ id: todoId });
+    expect(payloadCreator).toHaveBeenCalledWith(todoId);
+  });
+
+  it('Factory should accept a metaCreator', () => {
+    const metaCreator = jasmine.createSpy('metaCreator')
+      .and.callFake(metaThing => ({ id: metaThing }));
+
+    const deleteTodo = createAction('@@todos/:id | delete', null, metaCreator);
+    const metaThing = 'Hello World';
+
+    expect(deleteTodo(null, metaThing).meta).toEqual({ id: metaThing });
+    expect(metaCreator).toHaveBeenCalledWith(metaThing);
+  });
+
   describe('actionCreator', () => {
     it('should have a property type', () => {
       expect(createAction(type)).toHaveProperty('type', type);