IDBRequest

IDBRequest is a JavaScript interface in the IndexedDB API that represents an asynchronous operation request. It is the generic request object returned by many operations on IndexedDB objects, including methods on IDBDatabase, IDBObjectStore, and IDBIndex such as add, put, get, delete, clear, and cursor operations. It is also used by the initial open request when opening a database.

The IDBRequest object exposes several properties. readyState indicates whether the operation is still pending or has completed, with possible values of "pending" or "done". result holds the outcome of the operation and is available when the request completes successfully. error contains a DOMException describing any failure that occurred during the operation. The source property refers to the object that initiated the request, such as an IDBDatabase, an IDBObjectStore, or an IDBIndex.

IDBRequest implements the EventTarget interface and provides the event handlers onsuccess and onerror to respond to completion or failure. Developers may also attach listeners with addEventListener for the "success" and "error" events. When a request completes successfully, the result property contains the data produced by the operation (for example, a retrieved value or a generated key for add). If an error occurs, the error property contains the corresponding exception.

IDBOpenDBRequest is a specialized subtype of IDBRequest used for opening databases, which may expose additional events such as blocked. Overall, IDBRequest serves as the core mechanism for handling asynchronous outcomes in IndexedDB operations.