Update to fix edge cases of unwatch fn

Author: jordangarcia

src/reactor.js

@@ -201,10 +201,9 @@ class Reactor {
 
       dirtyStores.forEach(id => {
         const entries = this.observerState.getIn(['stores', id])
-        if (!entries) {
-          return
+        if (entries) {
+          set.union(entries)
         }
-        set.union(entries)
       })
     })
 
@@ -219,11 +218,14 @@ class Reactor {
       const currValue = currEvaluateResult.result
 
       if (!Immutable.is(prevValue, currValue)) {
-        const handlers = this.observerState.getIn(['gettersMap', getter])
-          .map(observerId => this.observerState.getIn(['observersMap', observerId, 'handler']))
-           // don't notify here in the case a handler called unobserve on another observer
-
-        handlers.forEach(handler => handler.call(null, currValue))
+        const observerIds = this.observerState.getIn(['gettersMap', getter], [])
+        observerIds.forEach(observerId => {
+          const handler = this.observerState.getIn(['observersMap', observerId, 'handler'])
+          // don't notify here in the case a handler called unobserve on another observer
+          if (handler) {
+            handler.call(null, currValue)
+          }
+        })
       }
     })
 

src/reactor/fns.js

@@ -177,7 +177,6 @@ exports.addObserver = function(observerState, getter, handler) {
 
   if (storeDeps.size === 0) {
     // no storeDeps means the observer is dependent on any of the state changing
-
     updatedObserverState = updatedObserverState.updateIn(['any'], getters => getters.add(getter))
   } else {
     updatedObserverState = updatedObserverState.withMutations(map => {
@@ -246,24 +245,34 @@ exports.removeObserverByEntry = function(observerState, entry) {
     const getter = entry.get('getter')
     const storeDeps = entry.get('storeDeps')
 
-    map.updateIn(['gettersMap', getter], observerIds => observerIds.remove(id));
-
-    if (map.getIn(['gettersMap', getter]).size <= 0) {
+    const observerIds = map.getIn(['gettersMap', getter])
+    if (!observerIds) {
+      // getter doesn't exist if reactor.reset() is called before the unwatchFn()
+      return
+    }
+    const updatedObserverIds = observerIds.remove(id)
+    map.setIn(['gettersMap', getter], updatedObserverIds)
 
+    if (updatedObserverIds.size === 0) {
+      // all observers have been removed for this getter, remove other entries
       if (storeDeps.size === 0) {
         // no storeDeps means the observer is dependent on any of the state changing
         map.update('any', getters => getters.remove(getter));
       } else {
         storeDeps.forEach(storeId => {
-          map.updateIn(['stores', storeId]
-            , getters => getters.remove(getter) )
+          map.updateIn(['stores', storeId], getters => {
+            if (getters) {
+              // check to make sure the getters Set exists for this store,
+              // in the case of reactor.reset() is called before the unwatchFn()
+              return getters.remove(getter)
+            }
+            return getters
+          })
         })
       }
-
     }
 
     map.removeIn(['observersMap', id])
-
   })
 }