IDBCursor: primaryKey property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2021.

Note: This feature is available in Web Workers.

The primaryKey read-only property of the IDBCursor interface returns the cursor's current effective key. If the cursor is currently being iterated or has iterated outside its range, this is set to undefined. The cursor's primary key can be any data type.

Value

A value of any data type.

Exceptions

InvalidStateError DOMException: Thrown if the cursor is advancing or has finished.

Examples

In this simple fragment we create a transaction, retrieve an object store, then use a cursor to iterate through all the records in the object store. Within each iteration we log the primary key of the cursor to the console.

The cursor does not require us to select the data based on a key; we can just grab all of it. Also note that in each iteration of the loop, you can grab data from the current record under the cursor object using cursor.value.foo. For a complete working example, see our IDBCursor example (View the example live).

function displayData() {
  const transaction = db.transaction(["rushAlbumList"], "readonly");
  const objectStore = transaction.objectStore("rushAlbumList");

  objectStore.openCursor().onsuccess = (event) => {
    const cursor = event.target.result;
    if (cursor) {
      const listItem = document.createElement("li");
      listItem.textContent = `${cursor.value.albumTitle}, ${cursor.value.year}`;
      list.appendChild(listItem);

      console.log(cursor.primaryKey);
      cursor.continue();
    } else {
      console.log("Entries all displayed.");
    }
  };
}

Specifications

Specification
Indexed Database API 3.0 # ref-for-dom-idbcursor-primarykey①

Browser compatibility

BCD tables only load in the browser