Merge pull request #65 from akiellor/fix-dropping-of-effects

FIX #64: Fix dropping of effects by detecting if an effect is already scheduled.

modules/effects.js

@@ -52,6 +52,15 @@ export function isEffect(object) {
   return object ? object[isEffectSymbol] : false;
 }
 
+/**
+ * Determines id the effect object is of type none
+ * @param {Object} The object to inspect.
+ * @returns {Boolean} Whether the object is a none effect.
+ */
+export function isNone(object) {
+  return object ? object.type === effectTypes.NONE : false;
+}
+
 /**
  * Creates a noop effect.
  * @returns {Object} An effect of type NONE, essentially a no-op.

modules/install.js

@@ -13,6 +13,7 @@ import {
   batch,
   none,
   isEffect,
+  isNone,
   effectToPromise,
 } from './effects';
 
@@ -28,7 +29,11 @@ export function install() {
     const liftReducer = (reducer) => (state, action) => {
       const result = reducer(state, action);
       const [model, effect] = liftState(result);
-      currentEffect = effect;
+      if (isNone(currentEffect)) {
+        currentEffect = effect
+      } else {
+        currentEffect = batch([currentEffect, effect]);
+      }
       return model;
     };
 

test/index.test.js

@@ -97,6 +97,40 @@ test('a looped action gets dispatched after the action that initiated it is redu
     });
 });
 
+test('Effects are proccessed in the order they are recieved', (t) => {
+  t.plan(1);
+
+  const reducer = function (state = {}, action) {
+    switch (action.type) {
+      case 'LOOPED_BEGIN':
+        return loop(
+          {...state, done: false},
+          Effects.constant({type: 'LOOPED_END'})
+        )
+      case 'LOOPED_END':
+        return {...state, done: true};
+      default:
+        return state
+    }
+  };
+
+  const store = finalCreateStore(reducer, {});
+
+  let needsToFire = true;
+  store.subscribe(function() {
+    if (needsToFire) {
+      needsToFire = false;
+      store.dispatch({type: 'SOME_OTHER_ACTION'});
+    }
+  });
+
+  const dispatchPromise = store.dispatch({type: 'LOOPED_BEGIN'});
+  dispatchPromise.then(function(r) {
+    const state = store.getState();
+    t.equal(state.done, true);
+  });
+});
+
 test('Effects.lift', (t) => {
   const lowerAction = (name) => ({ type: 'LOWER', name });
   const upperAction = (arg, action) => ({ type: 'UPPER', arg, action });