ok risolto in questo modo:

codice:
const app = {


  init: function() {
    app.start();
  },


  start: function() {
    setInterval(async () => {
      const data = await app.playerNow();
      app.dataOnAir(data);
    }, 5000);
  },


  playerNow: async function() {
    const url = "https://www.radiomatese.it/script/app/details.php";
    const response = await fetch(url);
    if (response.ok) {
      return response.json();
    }
  },
  
  dataOnAir: function(data) {
    console.log(data);
  }


};


app.init();