IDBObjectStore: count() method
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.
Note: This feature is available in Web Workers
Syntax
js
count()
count(query)
Parameters
query
Optional-
A key or
IDBKeyRange
object that specifies a range of records you want to count.
Return value
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.
Exceptions
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.
Examples
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.
js
const transaction = db.transaction(["fThings"], "readonly");
const objectStore = transaction.objectStore("fThings");
const countRequest = objectStore.count();
countRequest.onsuccess = () => {
console.log(countRequest.result);
};
Specifications
Specification |
---|
Indexed Database API 3.0 # ref-for-dom-idbobjectstore-count① |
Browser compatibility
BCD tables only load in the browser
See also
- 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).