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.
Note: This feature is available in Web Workers
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.
Note: This feature is available in Web Workers
lowerBound(lower) lowerBound(lower, open)
specifies the lower bound of the new key range.
indicates whether the lower bound excludes the endpoint value. The default is false.
IDBKeyRange
: The newly created key range.
This method may raise a DOMException
of the following type:
Exception | Description |
---|---|
DataError |
The value parameter passed was 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);
— 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() { 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.'); } }; };
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lowerBound |
23
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12
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10
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10
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15
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7
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4.4
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25
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22
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14
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8
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1.5
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IDBDatabase
IDBTransaction
IDBKeyRange
IDBObjectStore
IDBCursor
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https://developer.mozilla.org/en-US/docs/Web/API/IDBKeyRange/lowerBound