docs($rootScope): add note about watching File objects

- Add note recommending against watching `File` objects with deep watchers Closes #15440
2016-11-26 23:35:12 -08:00
parent 4059600d20
commit 9f61e74be3
1 changed files with 2 additions and 0 deletions
@@ -297,6 +297,8 @@ function $RootScopeProvider() {
       *   according to the {@link angular.equals} function. To save the value of the object for
       *   later comparison, the {@link angular.copy} function is used. This therefore means that
       *   watching complex objects will have adverse memory and performance implications.
+       * - This should not be used to watch for changes in objects that are
+       *   or contain [File](https://developer.mozilla.org/docs/Web/API/File) objects due to limitations with {@link angular.copy `angular.copy`}.
       * - The watch `listener` may change the model, which may trigger other `listener`s to fire.
       *   This is achieved by rerunning the watchers until no changes are detected. The rerun
       *   iteration limit is 10 to prevent an infinite loop deadlock.