dom / latest / idbrequest / error_event.html /

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

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
error_event
23
12
10
10
15
7
4.4
25
22
14
8
1.5

See also

© 2005–2021 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/IDBRequest/error_event

Name Web APIs
Version
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Last Updated 2022-04-27T09:33:08Z