Firebase doesn't catch error ( When pushing json offline )

Question

I'm trying to make an alert window saying there's an error, When trying to post a message offline. But the catch doesn't seem to ever work, Maybe it just works in other cases? here's my code :

  return (dispatch) => {
    dispatch({
      type: POST_TO_DB,
    });
    firebase.database().ref(locationInDB).push(object)
    .then((data) => {
      dispatch({
        type: POST_TRADE_TO_DB_SUCCESS,
      }); // success
    })
    .catch((err) => {
      console.log("failed to post...")
      dispatch({
        type: POST_TRADE_TO_DB_FAILED,
      }); // failed
    });
  };

Is there an alternative? Or am I doing something wrong?

Answer 1

When there is no network connection, the Firebase client will keep the pending write in memory until the network connection is restored, at which point it will complete the write.

The catch() clause is triggered if the write fails on the server, not when it can't complete.

Also see:

• To detect if the client is connected to the Firebase backend, see Detect if Firebase connection is lost/regained
• Firebase synchronisation of locally-modified data: handling errors & global status