feat(Adapters): Adds support for Epic input/output adapters.\nThis al…

…lows us to support RxJS v4 via https://github.com/redux-observable/redux-observable-adapter-rxjs-v4 (#85)

README.md

@@ -13,7 +13,7 @@
 ## Install
 
 This has a peer dependencies of `rxjs@5.0.*` and `redux`, which will have to be installed
-as well. **It is not currently compatible with RxJS v4**
+as well. Support for RxJS v4 can temporarily be provided by [an optional adapter](https://github.com/redux-observable/redux-observable-adapter-rxjs-v4).
 
 ```sh
 npm install --save redux-observable

docs/FAQ.md

@@ -13,19 +13,17 @@
 ## General
 
 <a id="general-rxjs-v4"></a>
-### Does this work with RxJS 4/most.js/bacon.js? 
+### Does this work with RxJS 4/most.js/bacon.js/etc? 
 
 ##### RxJS v4
 
-Not out of box. We'd love to provide an elegant solution for this soon; ideally [RxJS v4 would add interop with `Symbol.observable`](https://github.com/Reactive-Extensions/RxJS/issues/1225).
+Not out of box, but we provide an adapter [redux-observable-adapter-rxjs-v4](https://github.com/redux-observable/redux-observable-adapter-rxjs-v4) you can install to add support temporarily while you transition to RxJS v5. Please upgrade to v5 as soon as possible as we do not plan to support this long-term.
 
 ##### most.js
-
-We believe so, but this is currently unconfirmed! (please let us know) [most.js supports interop](https://github.com/cujojs/most/blob/master/docs/api.md#draft-es-observable-interop) with the proposed ECMAScript Observable spec which RxJS builds on top of.
-
 ##### bacon.js
+##### etc.
 
-Not out of box. Some work has been done to make [bacon.js support](https://github.com/baconjs/bacon.js/issues/633) the `Symbol.observable` interop point.
+It should be possible for you to create an adapter to add support. See [redux-observable-adapter-rxjs-v4](https://github.com/redux-observable/redux-observable-adapter-rxjs-v4) for reference.
 
 <a id="miscellaneous-thunkservables-deprecated"></a>
 ### Why were thunkservables deprecated? 

src/createEpicMiddleware.js

@@ -5,9 +5,20 @@ import { switchMap } from 'rxjs/operator/switchMap';
 import { ActionsObservable } from './ActionsObservable';
 import { EPIC_END } from './EPIC_END';
 
-export function createEpicMiddleware(epic) {
-  const actionsSubject = new Subject();
-  const action$ = new ActionsObservable(actionsSubject);
+const defaultAdapter = {
+  input: action$ => action$,
+  output: action$ => action$
+};
+
+const defaultOptions = {
+  adapter: defaultAdapter
+};
+
+export function createEpicMiddleware(epic, { adapter = defaultAdapter } = defaultOptions) {
+  const input$ = new Subject();
+  const action$ = adapter.input(
+    new ActionsObservable(input$)
+  );
   const epic$ = new BehaviorSubject(epic);
   let store;
 
@@ -16,7 +27,7 @@ export function createEpicMiddleware(epic) {
 
     return next => {
       if (typeof epic === 'function') {
-        epic$::switchMap(epic => epic(action$, store))
+        epic$::switchMap(epic => adapter.output(epic(action$, store)))
           .subscribe(store.dispatch);
       }
 
@@ -30,7 +41,7 @@ export function createEpicMiddleware(epic) {
           return out$.subscribe(store.dispatch);
         } else {
           const result = next(action);
-          actionsSubject.next(action);
+          input$.next(action);
           return result;
         }
       };

test/createEpicMiddleware-spec.js

@@ -273,4 +273,24 @@ describe('createEpicMiddleware', () => {
       done();
     }, 100);
   });
+
+  it('supports an adapter for Epic input/output', () => {
+    const reducer = (state = [], action) => state.concat(action);
+    const epic = input => input + 1;
+
+    const adapter = {
+      input: () => 1,
+      output: value => of({
+        type: value + 1
+      })
+    };
+    const middleware = createEpicMiddleware(epic, { adapter });
+
+    const store = createStore(reducer, applyMiddleware(middleware));
+
+    expect(store.getState()).to.deep.equal([
+      { type: '@@redux/INIT' },
+      { type: 3 }
+    ]);
+  });
 });