The index()
method of the IDBObjectStore
interface opens a named index in the current object store, after which it can be used to, for example, return a series of records sorted by that index using a cursor.
Syntax
var index = objectStore.index(name);
Parameters
- name
- The name of the index to open.
Return value
An IDBIndex
object for accessing the index.
Exceptions
This method may raise a DOMException
of one of the following types:
Exception | Description |
---|---|
InvalidStateError |
The source object store has been deleted, or the transaction for the object store has finished. |
NotFoundError |
There is no index with the given name (case-sensitive) in the database. |
Example
In the following example we open a transaction and an object store, then get the index lName
from a simple contacts database. We then open a basic cursor on the index using IDBIndex.openCursor
— this works the same as opening a cursor directly on an ObjectStore
using IDBObjectStore.openCursor
except that the returned records are sorted based on the index, not the primary key.
Finally, we iterate through each record, and insert the data into an HTML table. For a complete working example, see our IDBIndex-example demo repo (View the example live.)
function displayDataByIndex() { tableEntry.innerHTML = ''; var transaction = db.transaction(['contactsList'], 'readonly'); var objectStore = transaction.objectStore('contactsList'); var myIndex = objectStore.index('lName'); myIndex.openCursor().onsuccess = function(event) { var cursor = event.target.result; if(cursor) { var tableRow = document.createElement('tr'); tableRow.innerHTML = '<td>' + cursor.value.id + '</td>' + '<td>' + cursor.value.lName + '</td>' + '<td>' + cursor.value.fName + '</td>' + '<td>' + cursor.value.jTitle + '</td>' + '<td>' + cursor.value.company + '</td>' + '<td>' + cursor.value.eMail + '</td>' + '<td>' + cursor.value.phone + '</td>' + '<td>' + cursor.value.age + '</td>'; tableEntry.appendChild(tableRow); cursor.continue(); } else { console.log('Entries all displayed.'); } }; };
Specification
Specification | Status | Comment |
---|---|---|
Indexed Database API 2.0 The definition of 'index()' in that specification. |
Recommendation | |
Indexed Database API Draft The definition of 'index()' in that specification. |
Recommendation |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
index | Chrome
Full support
24
| Edge Full support 12 | Firefox
Full support
16
| IE Partial support 10 | Opera Full support 15 | Safari Full support 7 | WebView Android
Full support
Yes
| Chrome Android
Full support
25
| Firefox Android Full support 22 | Opera Android Full support 14 | Safari iOS Full support 8 | Samsung Internet Android
Full support
1.5
|
Legend
- Full support
- Full support
- Partial support
- Partial support
- Requires a vendor prefix or different name for use.
- Requires a vendor prefix or different name for use.
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.)