Baseline Widely available
Note: This feature is available in Web Workers.
The lowerBound()
static method of the IDBKeyRange
interface creates a new key range with only a lower bound. By default, it includes the lower endpoint value and is closed.
IDBKeyRange.lowerBound(lower)
IDBKeyRange.lowerBound(lower, open)
Parameters
lower
Specifies the lower bound of the new key range.
open
Optional
Indicates whether the lower bound excludes the endpoint value. The default is false.
IDBKeyRange
: The newly created key range.
DataError
DOMException
Thrown if the key associated with the lower
parameter is not a valid key.
The following example illustrates how you'd use a lower bound key range. Here we declare keyRangeValue = IDBKeyRange.lowerBound("F", false);
â a range that includes the value "F" and everything after 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. This means that the cursor will only retrieve the record with the key value "F" and all that come after it. If we used IDBKeyRange.lowerBound("F", true);
, then the range would not include "F"; only the values after 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.)
function displayData() {
const keyRangeValue = IDBKeyRange.lowerBound("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 Browser compatibility See also
IDBDatabase
IDBTransaction
IDBKeyRange
IDBObjectStore
IDBCursor
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