The count() method of the IDBObjectStore interface returns an IDBRequest object, and, in a separate thread, returns the total number of records that match the provided key or IDBKeyRange. If no arguments are provided, it returns the total number of records in the store.

query Optional

A key or IDBKeyRange object that specifies a range of records you want to count.

An IDBRequest object on which subsequent events related to this operation are fired.

If the operation is successful, the value of the request's result property is the number of records that match the given query.

This method may raise a DOMException of one of the following types:

InvalidStateError DOMException

Thrown if this IDBObjectStore has been deleted.

TransactionInactiveError DOMException

Thrown if this IDBObjectStore's transaction is inactive.

DataError DOMException

Thrown if the specified key or key range is invalid.

In this simple fragment we create a transaction, retrieve an object store, then count the number of records in the store using count() — when the success handler fires, we log the count value (an integer) to the console.

const transaction = db.transaction(["fThings"], "readonly");
const objectStore = transaction.objectStore("fThings");

const countRequest = objectStore.count();
countRequest.onsuccess = () => {
  console.log(countRequest.result);
};

• Using IndexedDB
• Starting transactions: IDBDatabase
• Using transactions: IDBTransaction
• Setting a range of keys: IDBKeyRange
• Retrieving and making changes to your data: IDBObjectStore
• Using cursors: IDBCursor
• Reference example: To-do Notifications (View the example live).