IDBObjectStore.count()
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
var request = ObjectStore.count();
var request = ObjectStore.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.
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.
Example
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.
var transaction = db.transaction(['fThings'], 'readonly');
var objectStore = transaction.objectStore('fThings');
var countRequest = objectStore.count();
countRequest.onsuccess = function() {
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 example live.)