IDBTransaction: error event
The error
event is fired on IDBTransaction
when a request returns an error and the event bubbles up to the transaction object.
Note: To handle all the ways a transaction can fail, consider listening for the abort
event instead.
Syntax
Use the event name in methods like addEventListener()
, or set an event handler property.
js
addEventListener("error", (event) => {});
onerror = (event) => {};
Event type
A generic Event
.
Bubbling
This event bubbles to IDBDatabase
. The event.target
property refers to the IDBTransaction
object that bubbles up.
For more information, see Event bubbling and capture.
Examples
This example opens a database and tries to add a record, listening for the error
event for the add()
operation (this will occur if, for example, a record with the given taskTitle
already exists):
js
// Open the database
const dBOpenRequest = window.indexedDB.open("toDoList", 4);
dBOpenRequest.onupgradeneeded = (event) => {
const db = event.target.result;
// Create an objectStore for this database
const objectStore = db.createObjectStore("toDoList", {
keyPath: "taskTitle",
});
// define what data items the objectStore will contain
objectStore.createIndex("hours", "hours", { unique: false });
objectStore.createIndex("minutes", "minutes", { unique: false });
objectStore.createIndex("day", "day", { unique: false });
objectStore.createIndex("month", "month", { unique: false });
objectStore.createIndex("year", "year", { unique: false });
};
dBOpenRequest.onsuccess = (event) => {
const db = dBOpenRequest.result;
// open a read/write db transaction, ready for adding the data
const transaction = db.transaction(["toDoList"], "readwrite");
transaction.addEventListener("error", () => {
console.log(`Error adding new item: ${newItem.taskTitle}`);
});
const objectStore = transaction.objectStore("toDoList");
const newItem = {
taskTitle: "my task",
hours: 10,
minutes: 10,
day: 10,
month: "January",
year: 2020,
};
const objectStoreRequest = objectStore.add(newItem);
};
The same example, using the onerror
property instead of addEventListener()
:
js
// Open the database
const dBOpenRequest = window.indexedDB.open("toDoList", 4);
dBOpenRequest.onupgradeneeded = (event) => {
const db = event.target.result;
// Create an objectStore for this database
const objectStore = db.createObjectStore("toDoList", {
keyPath: "taskTitle",
});
// define what data items the objectStore will contain
objectStore.createIndex("hours", "hours", { unique: false });
objectStore.createIndex("minutes", "minutes", { unique: false });
objectStore.createIndex("day", "day", { unique: false });
objectStore.createIndex("month", "month", { unique: false });
objectStore.createIndex("year", "year", { unique: false });
};
dBOpenRequest.onsuccess = (event) => {
const db = dBOpenRequest.result;
// open a read/write db transaction, ready for adding the data
const transaction = db.transaction(["toDoList"], "readwrite");
transaction.onerror = () => {
console.log(`Error adding new item: ${newItem.taskTitle}`);
};
const objectStore = transaction.objectStore("toDoList");
const newItem = {
taskTitle: "my task",
hours: 10,
minutes: 10,
day: 10,
month: "January",
year: 2020,
};
const objectStoreRequest = objectStore.add(newItem);
};
Browser compatibility
BCD tables only load in the browser