When checking if an observable has a pending notification, also compa…

…re the value. If it hasn't actually changed, don't force the notification.
knockout · Feb 10, 2017 · e9cc711 · e9cc711
1 parent c2eaf27
commit e9cc711
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Showing 2 changed files with 13 additions and 7 deletions.
diff --git a/src/subscribables/dependentObservable.js b/src/subscribables/dependentObservable.js
@@ -138,7 +138,7 @@ function computedBeginDependencyDetectionCallback(subscribable, id) {
         }
         // If the observable we've accessed has a pending notification, ensure we get notified of the actual final value (bypass equality checks)
         if (subscribable._notificationIsPending) {
-            subscribable._notifyNextChange = true;
+            subscribable._notifyNextChangeIfValueIsDifferent();
         }
     }
 }
@@ -333,10 +333,11 @@ var computedFn = {
             state.isStale = state.isDirty = false;
         }
     },
-    peek: function () {
-        // Peek won't re-evaluate, except while the computed is sleeping or to get the initial value when "deferEvaluation" is set.
+    peek: function (evaluate) {
+        // By default, peek won't re-evaluate, except while the computed is sleeping or to get the initial value when "deferEvaluation" is set.
+        // Pass in true to evaluate if needed.
         var state = this[computedState];
-        if ((state.isDirty && !state.dependenciesCount) || (state.isSleeping && this.haveDependenciesChanged())) {
+        if ((state.isDirty && (evaluate || !state.dependenciesCount)) || (state.isSleeping && this.haveDependenciesChanged())) {
             this.evaluateImmediate();
         }
         return state.latestValue;

diff --git a/src/subscribables/subscribable.js b/src/subscribables/subscribable.js
@@ -92,7 +92,7 @@ var ko_subscribable_fn = {
 
     limit: function(limitFunction) {
         var self = this, selfIsObservable = ko.isObservable(self),
-            ignoreBeforeChange, previousValue, pendingValue, beforeChange = 'beforeChange';
+            ignoreBeforeChange, notifyNextChange, previousValue, pendingValue, beforeChange = 'beforeChange';
 
         if (!self._origNotifySubscribers) {
             self._origNotifySubscribers = self["notifySubscribers"];
@@ -107,9 +107,9 @@ var ko_subscribable_fn = {
             if (selfIsObservable && pendingValue === self) {
                 pendingValue = self._evalIfChanged ? self._evalIfChanged() : self();
             }
-            var shouldNotify = self._notifyNextChange || self.isDifferent(previousValue, pendingValue);
+            var shouldNotify = notifyNextChange || self.isDifferent(previousValue, pendingValue);
 
-            self._notifyNextChange = ignoreBeforeChange = false;
+            notifyNextChange = ignoreBeforeChange = false;
 
             if (shouldNotify) {
                 self._origNotifySubscribers(previousValue = pendingValue);
@@ -128,6 +128,11 @@ var ko_subscribable_fn = {
                 self._origNotifySubscribers(value, beforeChange);
             }
         };
+        self._notifyNextChangeIfValueIsDifferent = function() {
+            if (self.isDifferent(previousValue, self.peek(true /*evaluate*/))) {
+                notifyNextChange = true;
+            }
+        };
     },
 
     hasSubscriptionsForEvent: function(event) {