IDBObjectStore: keyPath property

Note: This feature is available in Web Workers.

The keyPath read-only property of the IDBObjectStore interface returns the key path of this object store.

If this property is null, the application must provide a key for each modification operation.


Any value type.


In the following code snippet, we open a read/write transaction on our database and add some data to an object store using add(). After the object store has been created, we log objectStore.keyPath to the console. For a full working example, see our To-do Notifications app (view example live).

// Let us open our database
const DBOpenRequest ="toDoList", 4);

DBOpenRequest.onsuccess = (event) => {
  note.appendChild(document.createElement("li")).textContent =
    "Database initialized.";

  // store the result of opening the database in the db variable.
  // This is used a lot below
  db = DBOpenRequest.result;

  // Run the addData() function to add the data to the database

function addData() {
  // Create a new object ready to insert into the IDB
  const newItem = [
      taskTitle: "Walk dog",
      hours: 19,
      minutes: 30,
      day: 24,
      month: "December",
      year: 2013,
      notified: "no",

  // open a read/write db transaction, ready for adding the data
  const transaction = db.transaction(["toDoList"], "readwrite");

  // report on the success of the transaction completing, when everything is done
  transaction.oncomplete = (event) => {
    note.appendChild(document.createElement("li")).textContent =
      "Transaction completed.";

  transaction.onerror = (event) => {
    note.appendChild(document.createElement("li")).textContent =
      "Transaction not opened due to error. Duplicate items not allowed.";

  // create an object store on the transaction
  const objectStore = transaction.objectStore("toDoList");

  // Make a request to add our newItem object to the object store
  const objectStoreRequest = objectStore.add(newItem[0]);

  objectStoreRequest.onsuccess = (event) => {
    // report the success of our request
    note.appendChild(document.createElement("li")).textContent =
      "Request successful.";


Indexed Database API 3.0
# ref-for-dom-idbobjectstore-keypath①

Browser compatibility

BCD tables only load in the browser

See also