IDBDatabase: close event - Web APIs 编辑

The close event is fired on IDBDatabase when the database connection is unexpectedly closed. This could happen, for example, if the underlying storage is removed or if the user clears the database in the browser's history preferences.

Note that it is not fired if the database connection is closed normally using IDBDatabase.close().

Examples

This example opens a database and listens for the close event:

// 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;
  db.addEventListener('close', () => {
    console.log('Database connection closed');
  });

};

The same example, using the onclose 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;
  db.onclose = () => {
    console.log('Database connection closed');
  };

};

Browser compatibility

BCD tables only load in the browser

See also

• Using IndexedDB
• onclose event handler property