Make default reject handler always rethrow

src/index.js

@@ -27,7 +27,7 @@ function effects ({dispatch, getState}) {
   }
 
   function applyPromises (steps = [], q) {
-    return steps.reduce((q, [success = noop, failure = noop]) => q.then(val => maybeDispatch(success(val)), err => maybeDispatch(failure(err))), q)
+    return steps.reduce((q, [success = noop, failure = rethrow]) => q.then(val => maybeDispatch(success(val)), err => maybeDispatch(failure(err))), q)
   }
 
   function maybeDispatch (action) {
@@ -42,6 +42,7 @@ function promisify (val) {
 }
 
 function noop () {}
+function rethrow (err) { throw err; }
 
 /**
  * Action creator

test/index.js

@@ -25,6 +25,20 @@ test('should work', ({plan, equal}) => {
   }
 })
 
+test('unhandled rejections should pass through', ({plan, fail, pass}) => {
+  const store = create(effects, mw);
+
+  plan(1)
+  const promise = store.dispatch({type: 'EFFECT_COMPOSE', payload: {type: 'test'}, meta: {steps: [[x => x]]}})
+
+  promise.then(fail, pass);
+
+  function mw (api) {
+    return next => action =>
+      Promise.reject('alwaysReject')
+  }
+})
+
 /**
  * Helpers
  */