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
varrequest
= ObjectStore.count(); varrequest
= 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:
Exception | Description |
---|---|
InvalidStateError |
This IDBObjectStore has been deleted. |
TransactionInactiveError |
This IDBObjectStore 's transaction is inactive. |
DataError |
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); }
Specification
Specification | Status | Comment |
---|---|---|
Indexed Database API The definition of 'count()' in that specification. |
Recommendation | |
Indexed Database API 2.0 The definition of 'count()' in that specification. |
Editor's Draft |
Browser compatibility
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|---|
Basic support | 23webkit 24 (unprefixed) |
(Yes) | 10 moz 16.0 (16.0) |
10, partial | 15 | 7.1 |
Available in workers | (Yes) | ? | 37.0 (37.0) | ? | (Yes) | ? |
Indexed Database 2.0 | 58 | ? | ? | ? | 45 | ? |
Feature | Android Webview | Chrome for Android | Edge | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | 22.0 (22.0) | 1.0.1 | 10 | 22 | 8 |
Available in workers | (Yes) | (Yes) | ? | 37.0 (37.0) | (Yes) | ? | (Yes) | ? |
Indexed Database 2.0 | 58 | 58 | ? | ? | ? | ? | 45 | ? |
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.)