let persistence = new BeaconsMongoDbPersistence();
// ...

await persistence.open("test");

let beacon = <BeaconV1>{
    id: '1', 
    site_id: "0001",
    udi: "0002"

};

await persistence.set("test", beacon);
let item = persistence.getOneByUdi("test", "0002");
await persistence.close("test");
console.log(item.udi); // Result: 0002