test: 💍 add basic epic plugin tests

package.json

@@ -58,7 +58,7 @@
     "standard": "11.0.1",
     "redux": "3.7.2",
     "react-redux": "5.0.7",
-    "rxjs": "5.5.11",
+    "rxjs": "^6.2.1",
     "react": "16.4.0",
     "react-dom": "16.4.0",
     "@storybook/react": "3.4.7",

src/plugins/__tests__/epic.test.js

@@ -0,0 +1,68 @@
+import {createStore} from '../../'
+import pluginDispatch from '../dispatch'
+import pluginReducer from '../reducer'
+import pluginEpic from '../epic'
+
+const delay = time => new Promise(resolve => setTimeout(resolve, time))
+
+const createStoreWithPlugin = (epic, reducer = state => state) => {
+  return createStore({}, [
+    pluginDispatch(),
+    pluginReducer(reducer),
+    pluginEpic(epic)
+  ])
+}
+
+describe('plugin', () => {
+  describe('epics', () => {
+    it('is a function', () => {
+      expect(typeof pluginEpic).toBe('function')
+    })
+
+    it('throws if epic is not a function', () => {
+      expect(() => {
+        createStore(123)
+      }).toThrow()
+    })
+
+    it('works', async () => {
+      const log = []
+      const epic = (observable, store) => {
+        return {
+          subscribe (sink) {
+            observable.subscribe({
+              next: action => {
+                if (action.type === 'PING') {
+                  sink.next({type: 'PONG'})
+                }
+              }
+            })
+          }
+        }
+      }
+      const store = createStoreWithPlugin(epic)
+      const dispatch = store.dispatch
+
+      store.dispatch = (action) => {
+        log.push(action)
+        dispatch(action)
+      }
+
+      await delay(100)
+
+      store.dispatch({
+        type: 'PING'
+      })
+
+      store.dispatch({
+        type: 'NOT_PING'
+      })
+
+      expect(log).toEqual([
+        { type: 'PING' },
+        { type: 'PONG' },
+        { type: 'NOT_PING' }
+      ])
+    })
+  })
+})

src/plugins/epic.js

@@ -1,13 +1,19 @@
 import $$observable from 'symbol-observable'
 
 const plugin = (epic) => store => {
-  const dispatch = store.dispatch
+  if (process.env.NODE_ENV !== 'production') {
+    if (typeof epic !== 'function') {
+      throw new TypeError('epic must be a function that receives an observable and returns and observable.')
+    }
+  }
+
   const observable = {
     subscribe (observer) {
       const dispatch = store.dispatch
       let live = true
 
       store.dispatch = (action) => {
+        console.log('A', action)
         dispatch(action)
 
         if (live) {
@@ -27,7 +33,9 @@ const plugin = (epic) => store => {
     }
   }
 
-  epic(observable, store)(dispatch)
+  epic(observable, store).subscribe({
+    next: (action) => store.dispatch(action)
+  })
 }
 
 export default plugin