IDBIndex.getKey()

The getKey() method of the IDBIndex interface returns an IDBRequest object, and, in a separate thread, finds either the primary key that corresponds to the given key in this index or the first corresponding primary key, if key is set to an IDBKeyRange.

If a primary key is found, it is set as the result of the request object. Note that this doesn't return the whole record as IDBIndex.get does.

Note: This feature is available in Web Workers.

Syntax

var request = myIndex.getKey(key);

Parameters

key Optional
A key or IDBKeyRange that identifies a record to be retrieved. If this value is null or missing, the browser will use an unbound key range.

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
TransactionInactiveError This IDBIndex's transaction is inactive.
DataError

The key or key range provided contains an invalid key.

InvalidStateError The IDBIndex has been deleted or removed.

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.

myIndex.getKey('Bungle') is then used to retrieve the primary key of the record with an lName of Bungle, and the result of that request is logged to the console when its success callback returns.

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'); 
  var getKeyRequest = myIndex.getKey('Bungle');
  getKeyRequest.onsuccess = function() {
    console.log(getKeyRequest.result);
  }

  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 'getKey()' in that specification.
Recommendation
Indexed Database API Draft
The definition of 'getKey()' in that specification.
Recommendation

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
getKeyChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE Partial support 10Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android Full support 25Firefox Android Full support 22Opera Android Full support 14Safari iOS Full support 8Samsung 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