IDBCursor.advance()
The advance()
method of the IDBCursor
interface sets the number of times a cursor should move
its position forward.
Note: This feature is available in Web Workers
Syntax
cursor.advance(count);
Parameters
count
-
The number of times to move the cursor forward.
Exceptions
This method may raise a DOMException
of one of the following types:
TransactionInactiveError
DOMException
-
Thrown if this IDBCursor's transaction is inactive.
TypeError
DOMException
-
Thrown if the value passed into the
count
parameter was zero or a negative number. InvalidStateError
DOMException
-
Thrown if the cursor is currently being iterated or has iterated past its end.
Example
In this simple fragment we create a transaction, retrieve an object store, then use a
cursor to iterate through the records in the object store. Here we use
cursor.advance(2)
to jump 2 places forward each time, meaning that only
every other result will be displayed. advance()
works in a similar way to
IDBCursor.continue
, except that it allows you to jump multiple records at
a time, not just always go onto the next record.
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 advanceResult() {
list.textContent = '';
const transaction = db.transaction(['rushAlbumList'], "readonly");
const objectStore = transaction.objectStore('rushAlbumList');
objectStore.openCursor().onsuccess = function(event) {
const cursor = event.target.result;
if(cursor) {
const listItem = document.createElement('li');
listItem.innerHTML = '<strong>' + cursor.value.albumTitle + '</strong>, ' + cursor.value.year;
list.appendChild(listItem);
cursor.advance(2);
} else {
console.log('Every other entry displayed.');
}
};
};
Specifications
Specification |
---|
Indexed Database API 3.0 # ref-for-dom-idbcursor-advance① |
Browser compatibility
BCD tables only load in the browser
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.)