The direction read-only property of the IDBCursor interface is a DOMString that returns the direction of traversal of the cursor (set using IDBObjectStore.openCursor for example). See the Values section below for possible values.
Syntax
var direction = cursor.direction;
Value
A string (defined by the IDBCursorDirection enum) indicating the direction in which the cursor is traversing the data. Possible values are:
| Value | Description |
|---|---|
next |
This direction causes the cursor to be opened at the start of the source. |
nextunique |
This direction causes the cursor to be opened at the start of the source. For every key with duplicate values, only the first record is yielded. |
prev |
This direction causes the cursor to be opened at the end of the source. |
prevunique |
This direction causes the cursor to be opened at the end of the source. For every key with duplicate values, only the first record is yielded. |
Example
In this simple fragment we create a transaction, retrieve an object store, then use a cursor to iterate through all the records in the object store. Within each iteration we log the direction of the cursor, something like this:
prev
Note: we can't change the direction of travel of the cursor using the direction property, as it is read-only. We specify the direction of travel using the 2nd argument of IDBObjectStore.openCursor.
The cursor does not require us to select the data based on a key; we can just grab all of it. Also note that in each iteration of the loop, you can grab data from the current record under the cursor object using cursor.value.foo. For a complete working example, see our IDBCursor example (view example live.)
function backwards() {
list.innerHTML = '';
var transaction = db.transaction(['rushAlbumList'], 'readonly');
var objectStore = transaction.objectStore('rushAlbumList');
objectStore.openCursor(null,'prev').onsuccess = function(event) {
var cursor = event.target.result;
if(cursor) {
var listItem = document.createElement('li');
listItem.innerHTML = '<strong>' + cursor.value.albumTitle + '</strong>, ' + cursor.value.year;
list.appendChild(listItem);
console.log(cursor.direction);
cursor.continue();
} else {
console.log('Entries displayed backwards.');
}
};
};
Specifications
| Specification | Status | Comment |
|---|---|---|
| Indexed Database API The definition of 'direction' in that specification. |
Recommendation | |
| Indexed Database API 2.0 The definition of 'direction' in that specification. |
Editor's Draft |
Browser compatibility
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|---|
| Basic support | 23webkit 24 |
(Yes) | 10 moz 16.0 (16.0) |
10, partial | 15 | 7.1 |
| Available in workers | (Yes) | (Yes) | 37.0 (37.0) | ? | (Yes) | ? |
| Indexed Database 2.0 | 58 | ? | ? | ? | 45 | ? |
| Feature | Android Webview | Chrome for Android | Edge | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|---|---|
| Basic support | (Yes) | (Yes) | (Yes) | 22.0 (22.0) | 1.0.1 | 10 | 22 | 8 |
| Available in workers | (Yes) | (Yes) | (Yes) | 37.0 (37.0) | (Yes) | ? | (Yes) | ? |
| Indexed Database 2.0 | 58 | 58 | ? | ? | ? | ? | 45 | ? |
See also
- Using IndexedDB
- Starting transactions:
IDBDatabase - Using transactions:
IDBTransaction - Setting a range of keys:
IDBKeyRange - Retrieving and making changes to your data:
IDBObjectStore - Using cursors:
IDBCursor - Reference example: To-do Notifications (view example live.)