feat(scope): only evaluate constant $watch expressions once

1 files changed, 8 insertions, 0 deletions

diff --git a/src/ng/rootScope.js b/src/ng/rootScope.js
index b6a582bc..866b957e 100644
--- a/src/ng/rootScope.js
+++ b/src/ng/rootScope.js
@@ -300,6 +300,14 @@ function $RootScopeProvider(){
           watcher.fn = function(newVal, oldVal, scope) {listenFn(scope);};
         }
 
+        if (typeof watchExp == 'string' && get.constant) {
+          var originalFn = watcher.fn;
+          watcher.fn = function(newVal, oldVal, scope) {
+            originalFn.call(this, newVal, oldVal, scope);
+            arrayRemove(array, watcher);
+          };
+        }
+
         if (!array) {
           array = scope.$$watchers = [];
         }