IDBObjectStore: index() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

See full compatibility

Note: This feature is available in Web Workers.

The index() method of the IDBObjectStore interface opens a named index in the current object store, after which it can be used to, for example, return a series of records sorted by that index using a cursor.

Syntax

index(name)

Parameters

name: The name of the index to open.

Return value

An IDBIndex object for accessing the index.

Exceptions

InvalidStateError DOMException: Thrown if the source object store has been deleted, or the transaction for the object store has finished.
NotFoundError DOMException: Thrown if there is no index with the given name (case-sensitive) in the database.

Examples

In the following example we open a transaction and an object store, then get the index lName from a simple contacts database. We then open a basic cursor on the index using IDBIndex.openCursor — this works the same as opening a cursor directly on an ObjectStore using IDBObjectStore.openCursor except that the returned records are sorted based on the index, not the primary key.

Finally, we iterate through each record, and insert the data into an HTML table. For a complete working example, see our IDBIndex example in IndexedDB-examples demo repo (View the example live.)

function displayDataByIndex() {
  tableEntry.textContent = "";
  const transaction = db.transaction(["contactsList"], "readonly");
  const objectStore = transaction.objectStore("contactsList");

  const myIndex = objectStore.index("lName");
  myIndex.openCursor().onsuccess = (event) => {
    const cursor = event.target.result;
    if (cursor) {
      const tableRow = document.createElement("tr");
      for (const cell of [
        cursor.value.id,
        cursor.value.lName,
        cursor.value.fName,
        cursor.value.jTitle,
        cursor.value.company,
        cursor.value.eMail,
        cursor.value.phone,
        cursor.value.age,
      ]) {
        const tableCell = document.createElement("td");
        tableCell.textContent = cell;
        tableRow.appendChild(tableCell);
      }
      tableEntry.appendChild(tableRow);

      cursor.continue();
    } else {
      console.log("Entries all displayed.");
    }
  };
}

Specifications

Specification
Indexed Database API 3.0 # dom-idbobjectstore-index

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`index`	Chrome – Full support Chrome 23 (Release date: 2012-11-06) footnote Full support	Edge – Full support Edge 12 (Release date: 2015-07-29) footnote Full support	Firefox – Full support Firefox 10 (Release date: 2012-01-31) footnote Full support	Opera – Full support Opera 15 (Release date: 2013-07-02) footnote Full support	Safari – Full support Safari 8 (Release date: 2014-10-16) footnote Full support	Chrome Android – Full support Chrome Android 25 (Release date: 2013-02-27) footnote Full support	Firefox for Android – Full support Firefox for Android 22 (Release date: 2013-06-25) footnote Full support	Opera Android – Full support Opera Android 14 (Release date: 2013-05-21) footnote Full support	Safari on iOS – Full support Safari on iOS 8 (Release date: 2014-09-17) footnote Full support	Samsung Internet – Full support Samsung Internet 1.5 (Release date: 2013-09-25) footnote Full support	WebView Android – Full support WebView Android 4.4 (Release date: 2013-12-09) footnote Full support	WebView on iOS – Full support WebView on iOS 8 (Release date: 2014-09-17) footnote Full support

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Full support: Full support

IDBObjectStore: index() method

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