Unconditional Delivery Listeners

The where clause argument in the addUpdateListener method is optional. When it is not provided, the real-time database will deliver any object  which is being updated in the database's table:

Using Untyped Objects

const orderEventHandler = Backendless.Data.of('Order').rt();

const onObjectUpdate = object => 
                       console.log( 'an Order object has been updated. Object ID - ', object.objectId );

const onError = error => 
                console.log( 'An error has occurred -', error );

orderEventHandler.addUpdateListener( onObjectUpdate, onError );

Custom Class/Function

function Order() {
  this.objectId = undefined;
  this.orderAmount = 0;
}

const orderEventHandler = Backendless.Data.of( Order ).rt();

const onObjectUpdate = object => 
                       console.log( 'an Order object has been updated. Object ID - ', object.objectId );

const onError = error => 
                console.log( 'An error has occurred -', error );

orderEventHandler.addUpdateListener( onObjectUpdate, onError );