Warn when dispatching during middleware setup.

timdorr · timdorr · commit 50dd79005252 · 2016-03-05T21:38:15.000-05:00
diff --git a/src/applyMiddleware.js b/src/applyMiddleware.js
@@ -1,4 +1,5 @@
 import compose from './compose'
+import warning from './utils/warning'
 
 /**
  * Creates a store enhancer that applies middleware to the dispatch method
@@ -19,7 +20,13 @@ import compose from './compose'
 export default function applyMiddleware(...middlewares) {
   return (createStore) => (reducer, initialState, enhancer) => {
     var store = createStore(reducer, initialState, enhancer)
-    var dispatch = store.dispatch
+    var dispatch = (...args) => {
+      warning(
+        `Calling dispatch while constructing your middleware is discouraged. ` +
+        `Other middleware will not be applied to this dispatch.`
+      )
+      store.dispatch(...args)
+    }
     var chain = []
 
     var middlewareAPI = {
diff --git a/test/applyMiddleware.spec.js b/test/applyMiddleware.spec.js
@@ -5,6 +5,20 @@ import { addTodo, addTodoAsync, addTodoIfEmpty } from './helpers/actionCreators'
 import { thunk } from './helpers/middleware'
 
 describe('applyMiddleware', () => {
+  it('warns when dispatching during middleware setup', () => {
+    function dispatchingMiddleware(store) {
+      store.dispatch(addTodo('Dont dispatch in middleware setup'))
+      return next => action => next(action)
+    }
+
+    const spy = expect.spyOn(console, 'error')
+
+    applyMiddleware(dispatchingMiddleware)(createStore)(reducers.todos)
+
+    expect(spy.calls.length).toEqual(1)
+    spy.restore()
+  })
+
   it('wraps dispatch method with middleware once', () => {
     function test(spyOnMethods) {
       return methods => {
