 be impossible to sync
them back to the parent scope. By default, the <a href="api/ng/type/$rootScope.Scope#$watch"><code>$watch</code></a>
method is used for tracking changes, and the equality check is based on object identity.
However, if an object literal or an array literal is passed as the binding expression, the
equality check is done by value (using the <a href="api/ng/function/angular.equals"><code>angular.equals</code></a> function). It&#39;s also possible
to watch the evaluated value shallowly wit