[js][database] todo comments

lib/firebase.js

@@ -63,6 +63,8 @@ class FirebaseCore {
     const _name = (name || INTERNALS.STRINGS.DEFAULT_APP_NAME).toUpperCase();
 
     // return an existing app if found
+    // todo flag as deprecated - no longer need to initialize native apps
+    // todo in v4 remove deprecation and throw an error
     if (INTERNALS.APPS[_name]) return INTERNALS.APPS[_name];
 
     // only validate if app doesn't already exist

lib/modules/database/reference.js

@@ -415,6 +415,7 @@ export default class Reference extends ReferenceBase {
     return this.path;
   }
 
+  // TODO should check query modifiers and if same app instance
   /**
    * Returns whether another Reference represent the same location and are from the
    * same instance of firebase.app.App - multiple firebase apps not currently supported.