IDBKeyRange: upperBound() static method

upper

Specifies the upper bound of the new key range.

open Optional

Indicates whether the upper bound excludes the endpoint value. The default is false.

IDBKeyRange: The newly created key range.

DataError DOMException

Thrown if the key associated with the upper parameter is not a valid key.

The following example illustrates how you'd use an upper bound key range. Here we declare keyRangeValue = IDBKeyRange.upperBound("F"); — a range that includes the value "F" and everything before it. We open a transaction (using IDBTransaction) and an object store, and open a Cursor with IDBObjectStore.openCursor, declaring keyRangeValue as its optional key range value.

If we used IDBKeyRange.upperBound("F", true);, then the range excludes "F"; and instead only includes the values before it.

function displayData() {
  const keyRangeValue = IDBKeyRange.upperBound("F");

  const transaction = db.transaction(["fThings"], "readonly");
  const objectStore = transaction.objectStore("fThings");

  objectStore.openCursor(keyRangeValue).onsuccess = (event) => {
    const cursor = event.target.result;
    if (cursor) {
      const listItem = document.createElement("li");
      listItem.textContent = `${cursor.value.fThing}, ${cursor.value.fRating}`;
      list.appendChild(listItem);

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

• Using IndexedDB
• Starting transactions: IDBDatabase
• Using transactions: IDBTransaction
• Setting a range of keys: IDBKeyRange
• Retrieving and making changes to your data: IDBObjectStore
• Using cursors: IDBCursor
• Reference example: To-do Notifications (View the example live).