Web/API/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 ([[../../../../../../../mdn.github.io/IDBIndex-example/index|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 2.0The definition of 'index()' in that specification.	Recommendation
Indexed Database API DraftThe definition of 'index()' in that specification.	Recommendation

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`index`	Chrome Full support 24 Full support 24 No support 23 — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25 Full support 25 No support 25 — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5 Full support 1.5 No support 1.5 — 7.0 Prefixed' Prefixed' Implemented with the vendor prefix: webkit

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.