IDBRequest: error event
The error
handler is executed when an error caused a request to fail.
This event is not cancelable and does not bubble.
Syntax
Use the event name in methods like addEventListener()
, or set an event handler property.
addEventListener('error', event => { });
onerror = event => { };
Event type
A generic Event
.
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):
// Open the database
const DBOpenRequest = window.indexedDB.open('toDoList', 4);
DBOpenRequest.addEventListener('upgradeneeded', event => {
const db = event.target.result;
db.onerror = () => {
console.log('Error creating database');
};
// Create an objectStore for this database
var 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.addEventListener('success', event => {
const db = DBOpenRequest.result;
// open a read/write db transaction, ready for adding the data
const transaction = db.transaction(['toDoList'], 'readwrite');
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);
objectStoreRequest.addEventListener('error', () => {
console.log(`Error adding new item: ${newItem.taskTitle}`);
});
});
The same example, using the onerror
property instead of addEventListener()
:
// Open the database
const DBOpenRequest = window.indexedDB.open('toDoList', 4);
DBOpenRequest.onupgradeneeded = event => {
const db = event.target.result;
db.onerror = () => {
console.log('Error creating database');
};
// Create an objectStore for this database
var 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');
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);
objectStoreRequest.onerror = () => {
console.log(`Error adding new item: ${newItem.taskTitle}`);
};
};
Browser compatibility
BCD tables only load in the browser