Web/API/IDBindex/openCursor

From Get docs

The openCursor() method of the IDBIndex interface returns an IDBRequest object, and, in a separate thread, creates a cursor over the specified key range.


The method sets the position of the cursor to the appropriate record, based on the specified direction.

  • If the key range is not specified or is null, then the range includes all the records.
  • A success event is always fired on the result object.
    • If at least one record matches the key range, then the result property of the event is set to the new IDBCursorWithValue object; the value of the cursor object is set to a structured clone of the referenced value.
    • If no records match the key range then then the result property of the event is set to null.

Note: This feature is available in Web Workers.

Syntax

var request = myIndex.openCursor();
var request = myIndex.openCursor(range);
var request = myIndex.openCursor(range, direction);

Parameters

range Optional
A key or IDBKeyRange to use as the cursor's range. If nothing is passed, this will default to a key range that selects all the records in this object store.
direction Optional
The cursor's direction. See IDBCursor Constants for possible values.

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.
TypeError The value for the direction parameter is invalid.
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 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 'openCursor()' in that specification. Recommendation
Indexed Database API DraftThe definition of 'openCursor()' 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
openCursor

Chrome Full support 24


Full support 24


No support 23 — 24

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 ? — ?

Prefixed'

Prefixed' Implemented with the vendor prefix: webkit

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