IDBObjectStore.index()

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. 

Note: This feature is available in Web Workers.

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
The definition of 'index()' in that specification.
Recommendation  
Indexed Database API 2.0
The definition of 'index()' in that specification.
Recommendation  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support 24
Full support 24
No support 23 — 57
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — 57
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25
Full support 25
No support 25 — 57
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
Full support Yes
No support ? — 7.0
Prefixed
Prefixed Requires the vendor prefix: webkit

Legend

Full support  
Full support
See implementation notes.
See implementation notes.
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also

Document Tags and Contributors

Contributors to this page: fscholz, jpmedley, libbymc, inexorabletash, chrisdavidmills
Last updated by: fscholz,