IDBIndex.keyPath

This article is in need of a technical review.

The keyPath property of the IDBIndex interface returns the key path of the current index. If null, this index is not auto-populated.

Syntax

var myIndex = objectStore.index('index');
console.log(myIndex.keyPath);

Value

Any data type that can be used as a key path.

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.

The key path of the current index is logged to the console: it should be returned as lName.

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'); 
  console.log(myIndex.keyPath);

  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 'keyPath' in that specification.
Candidate Recommendation  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 23webkit
24
10 moz
16.0 (16.0)
10, partial 15 7.1
count() 23 22.0 (22.0) 10, partial 15 7.1
getAll() and getAllKeys() Not supported 24.0 (24.0)
behind dom.indexedDB.experimental  pref
Not supported Not supported Not supported
Feature Android Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support 4.4 22.0 (22.0) 1.0.1 10 22 Not supported
count() 4.4 22.0 (22.0) 1.0.1 10 22 Not supported
getAll() and getAllKeys() Not supported 24.0 (24.0)
behind dom.indexedDB.experimental  pref
1.1 behind
dom.indexedDB.experimental  pref
Not supported Not supported Not supported

Be careful in Chrome as it still implements the old specification along the new one. Similarly it still has the prefixed webkitIndexedDB property even if the unprefixed indexedDB is present.

See also

Document Tags and Contributors

Contributors to this page: freaktechnik, fscholz, chrisdavidmills
Last updated by: freaktechnik,