IDBRequest：result 属性

const title = "Walk dog";

// Open up a transaction as usual
const objectStore = db
  .transaction(["toDoList"], "readwrite")
  .objectStore("toDoList");

// Get the to-do list object that has this title as its title
const objectStoreTitleRequest = objectStore.get(title);

objectStoreTitleRequest.onsuccess = () => {
  // Grab the data object returned as the result
  const data = objectStoreTitleRequest.result;

  // Update the notified value in the object to "yes"
  data.notified = "yes";

  // Create another request that inserts the item
  // back into the database
  const updateTitleRequest = objectStore.put(data);

  // When this new request succeeds, run the displayData()
  // function again to update the display
  updateTitleRequest.onsuccess = () => {
    displayData();
  };
};