Not sure how to create model for this codes of java script. need to display a list with saved names and then be able to select favorute

function showFavorites() {
    favoritesList = JSON.parse(localStorage.getItem("saveData"));
    fetch(favoritesList[0].url)
      .then(response => response.json())
      .then(data => {
        console.log(data);
      });
  }

        
  function saveFavorites(item) {
    var flag = false;
    for (let i = 0; i < savedLaunches.length; i++) {
      if (savedLaunches[i].url == item.url) {
        flag = true;
      }
    }
    if (flag) {
      return;
    }
    savedLaunches.push(item);
    localStorage.setItem("saveData",JSON.stringify(savedLaunches));
  }