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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
  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.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
  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");
  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	8	4.4	25	22	14	8	1.5

Syntax

Event type

Examples

Browser compatibility

See also