IDBRequest: error property
The error
read-only property of the
IDBRequest
interface returns the error in the event of an unsuccessful
request.
Note: This feature is available in Web Workers
Value
A DOMException
or null
if there is no error. The following error names are returned
in the exception object:
AbortError
-
If you abort the transaction, then all requests still in progress receive this error.
ConstraintError
-
If you insert data that doesn't conform to a constraint. It's an exception type for creating stores and indexes. You get this error, for example, if you try to add a new key that already exists in the record.
QuotaExceededError
-
If you run out of disk quota and the user declined to grant you more space.
UnknownError
-
If the operation failed for reasons unrelated to the database itself. A failure due to disk IO errors is such an example.
VersionError
-
If you try to open a database with a version lower than the one it already has.
In addition to the error codes sent to the IDBRequest
object,
asynchronous operations can also raise exceptions. The list describes problems that
could occur when the request is being executed, but you might also encounter other
problems when the request is being made. For example, if the result is accessed
while the request is not completed, the InvalidStateError
exception is thrown.
Examples
The following example requests a given record title, onsuccess
gets the
associated record from the IDBObjectStore
(made available as
objectStoreTitleRequest.result
), updates one property of the record, and then puts the
updated record back into the object store. Also included at the bottom is an
onerror
function that reports what the error was if the request fails.
For a full working example, see our To-do Notifications app (View the example live).
js
const title = "Walk dog";
// Open up a transaction as usual
const objectStore = db
.transaction(["toDoList"], "readwrite")
.objectStore("toDoList");
// Get the to-do list with the specified title
const objectStoreTitleRequest = objectStore.get(title);
objectStoreTitleRequest.onsuccess = () => {
// Grab the data object returned as the result
const data = objectStoreTitleRequest.result;
// Update the notified value in the object to "yes"
data.notified = "yes";
// Create another request that inserts the item
// back into the database
const updateTitleRequest = objectStore.put(data);
// When this new request succeeds, run the displayData()
// function again to update the display
updateTitleRequest.onsuccess = () => {
displayData();
};
};
objectStoreTitleRequest.onerror = () => {
// If an error occurs with the request, log what it is
console.log(
`There has been an error with retrieving your data: ${objectStoreTitleRequest.error}`
);
};
Specifications
Specification |
---|
Indexed Database API 3.0 # ref-for-dom-idbrequest-error① |
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 the example live).