IDBKeyRange: upperBound() static method

Note: This feature is available in Web Workers.

The upperBound() static method of the IDBKeyRange interface creates a new upper-bound key range. By default, it includes the upper endpoint value and is closed.

Syntax

js
IDBKeyRange.upperBound(upper)
IDBKeyRange.upperBound(upper, open)

Parameters

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.

Return value

IDBKeyRange: The newly created key range.

Exceptions

DataError DOMException

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

Examples

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.

Note: For a more complete example allowing you to experiment with key range, have a look at our IDBKeyRange-example repo (view the example live too.)

js
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.");
    }
  };
}

Specifications

See also