IDBTransaction: error event

BaselineWidely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Theerror event is fired onIDBTransaction 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 theabort event instead.

Syntax

Use the event name in methods likeaddEventListener(), or set an event handler property.

addEventListener("error", (event) => { })onerror = (event) => { }

Event type

A genericEvent.

Bubbling

This event bubbles toIDBDatabase. Theevent.target property refers to theIDBTransaction object that bubbles up.

For more information, seeEvent bubbling.

Examples

This example opens a database and tries to add a record, listening for theerror event for theadd() operation (this will occur if, for example, a record with the giventaskTitle already exists):

// Open the databaseconst 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 theonerror property instead ofaddEventListener():

// Open the databaseconst 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);};