web api instance method

IDBObjectStore: deleteIndex() method

Available in workers

The deleteIndex() method of the 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 indexNames property.

Syntax

deleteIndex(indexName)

Parameters

indexName
- : The name of the existing index to remove.

Return value

None (undefined).

Exceptions

InvalidStateError DOMException
- : Thrown if the method was not called from a versionchange transaction mode callback.
TransactionInactiveError DOMException
- : Thrown if the transaction this IDBObjectStore belongs to is not active (e.g., has been deleted or removed.)
NotFoundError DOMException
- : Thrown if there is no index with the given name (case-sensitive) in the database.

Examples

In the following example you can see the onupgradeneeded handler being used to update the database structure if a database with a higher version number is loaded. 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

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.