Baseline Widely available
Note: This feature is available in Web Workers.
The openCursor()
method of the IDBObjectStore
interface returns an IDBRequest
object, and, in a separate thread, returns a new IDBCursorWithValue
object. Used for iterating through an object store with a cursor.
openCursor()
openCursor(query)
openCursor(query, direction)
Parameters
query
Optional
A key or IDBKeyRange
to be queried. If a single valid key is passed, this will default to a range containing only that key. If nothing is passed, this will default to a key range that selects all the records in this object store.
direction
Optional
A string telling the cursor which direction to travel. The default is next
. Valid values are:
next
The cursor is opened at the start of the store; then, the cursor returns all records, even duplicates, in the increasing order of keys.
nextunique
The cursor is opened at the start of the store; then, the cursor returns all records, that are not duplicates, in the increasing order of keys.
prev
The cursor is opened at the end of the store; then, the cursor returns all records, even duplicates, in the decreasing order of keys.
prevunique
The cursor is opened at the end of the store; then, the cursor returns all records, that are not duplicates, in the decreasing order of keys.
An IDBRequest
object on which subsequent events related to this operation are fired.
If the operation is successful, the value of the request's result
property is:
IDBCursorWithValue
object pointing at the first record matching the given querynull
if no matching records were found.This method may raise a DOMException
of one of the following types:
InvalidStateError
DOMException
Thrown if this IDBObjectStore
or IDBIndex
has been deleted.
TransactionInactiveError
DOMException
Thrown if this IDBObjectStore
's transaction is inactive.
DataError
DOMException
Thrown if the specified key or key range is invalid.
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:
const transaction = db.transaction("name", "readonly");
const objectStore = transaction.objectStore("name");
const request = objectStore.openCursor();
request.onsuccess = (event) => {
const cursor = event.target.result;
if (cursor) {
// cursor.value contains the current record being iterated through
// this is where you'd do something with the result
cursor.continue();
} else {
// no more results
}
};
Specifications Browser compatibility See also
IDBDatabase
IDBTransaction
IDBKeyRange
IDBObjectStore
IDBCursor
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