IDBTransaction: error event

{{ APIRef("IndexedDB") }}

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 {{domxref("IDBTransaction.abort_event", "abort")}} event instead.

Syntax

Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}} , or set an event handler property.

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

Event type

A generic {{domxref("Event")}} .

Bubbling

This event bubbles to {{domxref("IDBDatabase")}} . The event.target property refers to the {{domxref('IDBTransaction')}} object that bubbles up.

For more information, see Event bubbling.

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.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():

// 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);
};

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

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