Note: This feature is available in Web Workers.
The oldVersion read-only property of the IDBVersionChangeEvent interface returns the old version number of the database.
When the opened database doesn't exist yet, the value of oldVersion is 0.
A number containing a 64-bit integer.
const dbName = "sampleDB";
const dbVersion = 2;
const request = indexedDB.open(dbName, dbVersion);
request.onupgradeneeded = (e) => {
const db = request.result;
if (e.oldVersion < 1) {
db.createObjectStore("store1");
}
if (e.oldVersion < 2) {
db.deleteObjectStore("store1");
db.createObjectStore("store2");
}
// etc. for version < 3, 4…
};IDBDatabaseIDBTransactionIDBKeyRangeIDBObjectStoreIDBCursor