The lowerBound()
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.
Syntax
var myIDBKeyRange = IDBKeyRange.lowerBound(lower); var myIDBKeyRange = 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.
Return value
IDBKeyRange
: The newly created key range.
Exceptions
This method may raise a DOMException
of the following type:
Exception | Description |
---|---|
DataError |
The value parameter passed was not a valid key. |
Example
The following example illustrates how you'd use a lower bound key range. Here we declare keyRangeValue = IDBKeyRange.lowerBound("F", false);
— a range that includes the value "F" and everthing 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() { var keyRangeValue = IDBKeyRange.lowerBound("F"); var transaction = db.transaction(['fThings'], 'readonly'); var objectStore = transaction.objectStore('fThings'); objectStore.openCursor(keyRangeValue).onsuccess = function(event) { var cursor = event.target.result; if(cursor) { var listItem = document.createElement('li'); listItem.innerHTML = '<strong>' + cursor.value.fThing + '</strong>, ' + cursor.value.fRating; list.appendChild(listItem); cursor.continue(); } else { console.log('Entries all displayed.'); } }; };
Specification
Specification | Status | Comment |
---|---|---|
Indexed Database API 2.0 The definition of 'lowerBound()' in that specification. |
Recommendation | |
Indexed Database API Draft The definition of 'lowerBound()' in that specification. |
Recommendation |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
lowerBound | Chrome
Full support
24
| Edge Full support 12 | Firefox
Full support
16
| IE Partial support 10 | Opera Full support 15 | Safari Full support 7 | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 22 | Opera Android Full support 14 | Safari iOS Full support 8 | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
- Partial support
- Partial support
- Requires a vendor prefix or different name for use.
- Requires a vendor prefix or different name for use.
See also
- 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 example live.)