The IDBKeyRange
interface of the IndexedDB API represents a continuous interval over some data type that is used for keys. Records can be retrieved from IDBObjectStore
and IDBIndex
objects using keys or a range of keys. You can limit the range using lower and upper bounds. For example, you can iterate over all values of a key in the value range A–Z.
A key range can be a single value or a range with upper and lower bounds or endpoints. If the key range has both upper and lower bounds, then it is bounded; if it has no bounds, it is unbounded. A bounded key range can either be open (the endpoints are excluded) or closed (the endpoints are included). To retrieve all keys within a certain range, you can use the following code constructs:
Range | Code |
---|---|
All keys ≤ x | IDBKeyRange.upperBound (x) |
All keys < x | IDBKeyRange.upperBound (x, true) |
All keys ≥ y | IDBKeyRange.lowerBound (y) |
All keys > y | IDBKeyRange.lowerBound (y, true) |
All keys ≥ x && ≤ y | IDBKeyRange.bound (x, y) |
All keys > x &&< y | IDBKeyRange.bound (x, y, true, true) |
All keys > x && ≤ y | IDBKeyRange.bound (x, y, true, false) |
All keys ≥ x &&< y | IDBKeyRange.bound (x, y, false, true) |
The key = z | IDBKeyRange.only (z) |
A key is in a key range if the following conditions are true:
- The lower value of the key range is one of the following:
undefined
- Less than key value
- Equal to key value if
lowerOpen
isfalse
.
- The upper value of the key range is one of the following:
undefined
- Greater than key value
- Equal to key value if
upperOpen
isfalse
.
Methods
IDBKeyRange.bound()
- Creates a new key range with upper and lower bounds.
IDBKeyRange.includes()
- Returns a boolean indicating whether a specified key is inside the key range.
IDBKeyRange.only()
- Creates a new key range containing a single value.
IDBKeyRange.lowerBound()
- Creates a new key range with only a lower bound.
IDBKeyRange.upperBound()
- Creates a new upper-bound key range.
Properties
IDBKeyRange.lower
Read only- Lower bound of the key range.
IDBKeyRange.upper
Read only- Upper bound of the key range.
IDBKeyRange.lowerOpen
Read only- Returns false if the lower-bound value is included in the key range.
IDBKeyRange.upperOpen
Read only- Returns false if the upper-bound value is included in the key range.
Examples
The following example illustrates how you'd use a key range. Here we declare a keyRangeValue
as a range between values of "A" and "F". 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 records with keys inside that range. This range includes the values "A" and "F", as we haven't declared that they should be open bounds. If we used IDBKeyRange.bound("A", "F", true, true);, then the range would not include "A" and "F", only the values between them.
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.bound("A", "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.'); } }; };
Specifications
Specification | Status | Comment |
---|---|---|
Indexed Database API The definition of 'IDBKeyRange' in that specification. |
Recommendation |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 23webkit 24 |
10 moz 16.0 (16.0) |
10, partial | 15 | 7.1 |
Available in workers | (Yes) | 37.0 (37.0) | ? | (Yes) | ? |
includes() |
? | 47.0 (47.0) | ? | ? | ? |
Feature | Android | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | 4.4 | 22.0 (22.0) | 1.0.1 | 10 | 22 | 8 |
Available in workers | (Yes) | 37.0 (37.0) | (Yes) | ? | (Yes) | ? |
includes() |
? | ? | ? | ? | ? | ? |
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.)