Create simple observable SQLite method to retrieve list of rows

Ionic Framework
1

I need to create a simple observable method to retrieve list of rows by sql query but I have problem with sintax

This is my code thath create an array with my object


this.storage.executeSql("SELECT * FROM reservation", []).then(res => {

  let list = [];

  if (res.rows.length > 0) {

    for (var i = 0; i < res.rows.length; i++) { 
      //this is my custom function that create a custom object
      let myObject = convert(res.rows.item(i)); 
      list.push(res.rows.item(i));
    }

  } else {

    console.info("Nessuna scheda trovata");

  }
  
});

I want use obervable similar to…

this.db.getReservations().subscribe(data => {
  ... data is array of objects ...
})

How can I writ a method?

getReservations(): Observable <any> {
    
   ???

  }

My subscriber is:

this.getReservations().subscribe(data => {
  console.info("List of reservations: ", data);
})