types: add type definition #2

Author: distolma

README.md

@@ -53,4 +53,32 @@ let increment = store => {
 }
 
 export const store = createStore([increment, createEpicMiddleware(epics)]);
-```
+```
+
+Using TypeScript you can assign `Epic` interface to the function to specify `action` and `state` typing
+
+#### `epic.ts`
+```typescript
+import { combineEpics, ofEvent, Epic } from 'storeon-observable';
+import { mapTo, delay } from 'rxjs/operators'
+
+interface State {
+  isPinging: boolean;
+}
+
+const epic: Epic<State> = (action$, state$) => action$.pipe(
+  ofEvent('ping'),
+  delay(1000),
+  mapTo('pong'),
+);
+
+export const epics = combineEpics([epic]);
+```
+
+## Acknowledgments
+
+This module based on [redux-observable](https://github.com/redux-observable/redux-observable).
+
+## LICENSE
+
+[MIT](LICENCE)

index.d.ts

@@ -0,0 +1,12 @@
+import { Store } from 'storeon';
+import { Observable } from 'rxjs';
+
+export declare interface Epic<State = unknown> {
+    (action$: Observable<string>, state$: Observable<State>): Observable<string>;
+}
+
+export declare function createEpicMiddleware(rootEpic: Epic): (store: Store) => void;
+
+export declare function combineEpics(epics: Epic[]): Epic;
+
+export declare function ofEvent(key: string): (source: Observable<string>) => Observable<string>;