files/en-us/web/api/idbobjectstore/deleteindex/index.md
{{ APIRef("IndexedDB") }} {{AvailableInWorkers}}
The deleteIndex() method of the
{{domxref("IDBObjectStore")}} interface destroys the index with the specified name in
the connected database, used during a version upgrade.
Note that this method must be called only from a VersionChange transaction
mode callback. Note that this method synchronously modifies the
{{domxref("IDBObjectStore.indexNames")}} property.
deleteIndex(indexName)
indexName
None ({{jsxref("undefined")}}).
InvalidStateError {{domxref("DOMException")}}
versionchange transaction mode callback.TransactionInactiveError {{domxref("DOMException")}}
NotFoundError {{domxref("DOMException")}}
In the following example you can see
the {{domxref("IDBOpenDBRequest.upgradeneeded_event", "onupgradeneeded")}} handler being used to update the
database structure if a database with a higher version number is loaded.
{{domxref("IDBObjectStore.createIndex")}} is used to create new indexes on the object
store, after which we delete the unneeded old indexes with deleteIndex().
For a full working example, see our
To-do Notifications app (view example live).
let db;
// Let us open our database
const DBOpenRequest = window.indexedDB.open("toDoList", 4);
// these two event handlers act on the database being opened successfully, or not
DBOpenRequest.onerror = (event) => {
note.appendChild(document.createElement("li")).textContent =
"Error loading database.";
};
DBOpenRequest.onsuccess = (event) => {
note.appendChild(document.createElement("li")).textContent =
"Database initialized.";
// store the result of opening the database in the db variable. This is used a lot below
db = event.target.result;
// Run the displayData() function to populate the task list with all the to-do list data already in the IDB
displayData();
};
// This event handles the event whereby a new version of the database needs to be created
// Either one has not been created before, or a new version number has been submitted via the
// window.indexedDB.open line above
// it is only implemented in recent browsers
DBOpenRequest.onupgradeneeded = (event) => {
const db = event.target.result;
db.onerror = (event) => {
note.appendChild(document.createElement("li")).textContent =
"Error loading 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 });
objectStore.createIndex("notified", "notified", { unique: false });
objectStore.deleteIndex("seconds");
objectStore.deleteIndex("contact");
};
{{Specifications}}
{{Compat}}