auto update "last_modified"

[ahdat81]

mongodb has a feature where it auto updates a "last_modified" field whenever a record is updated. is there a similar feature here? if not, its there a preferred way to handle this? Getting the current date from the client will be inaccurate. I could watch for mutations on the server and update the record afterwards, but i think that'll cause every modification to trigger 2 update events (or even an infinite loop). I could get the server date before updating, but that could have problems too (if offline or temporarily not connected)

[appy-one]

You can prevent a loop by providing a context in your update:

db.ref('my_collection').on('notify_child_changed', ref => {
   const context = ref.context();
   if (context && context.lastModifiedEvent) {
      return; // Prevent recursive updates
   }
   // Update last_modified
   ref.context({ lastModifiedEvent: true }).update({ last_modified: Date.now() });
});

Also see Get triggering context of events