IDBIndex: getKey() 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.

Note: This feature is available inWeb Workers.

ThegetKey() method of theIDBIndexinterface returns anIDBRequest object, and, in a separate thread,finds either the primary key that corresponds to the given key in this index or thefirst corresponding primary key, ifkey is set to anIDBKeyRange.

If a primary key is found, it is set as theresult of the request object.Note that this doesn't return the whole record asIDBIndex.get does.

Syntax

getKey()getKey(key)

Parameters

keyOptional: A key orIDBKeyRange that identifies a record to be retrieved. Ifthis value is null or missing, the browser will use an unbound key range.

Return value

AnIDBRequest object on which subsequent events related to this operation are fired.

If the operation is successful, the value of the request'sresult property is the key for the first record matching the given key or key range.

Exceptions

This method may raise aDOMException of one of the following types:

TransactionInactiveErrorDOMException: Thrown if thisIDBIndex's transaction is inactive.
DataErrorDOMException: Thrown if the key or key range provided contains an invalid key.
InvalidStateErrorDOMException: Thrown if theIDBIndex has been deleted or removed.

Examples

In the following example we open a transaction and an object store, then get theindexlName from a simple contacts database. We then open a basic cursor onthe index usingIDBIndex.openCursor — this works the same as opening acursor directly on anObjectStore usingIDBObjectStore.openCursor except that the returned records are sortedbased on the index, not the primary key.

myIndex.getKey('Bungle') is then used to retrieve the primary key of therecord with anlName ofBungle, and the result of that requestis logged to the console when its success callback returns.

Finally, we iterate through each record, and insert the data into an HTML table. For acomplete working example, see ourIndexedDB-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");  const getKeyRequest = myIndex.getKey("Bungle");  getKeyRequest.onsuccess = () => {    console.log(getKeyRequest.result);  };  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.");    }  };}