The cmp()
method of the IDBFactory
interface compares two values as keys to determine equality and ordering for IndexedDB operations, such as storing and iterating.
Note: Do not use this method for comparing arbitrary JavaScript values, because many JavaScript values are either not valid IndexedDB keys (booleans and objects, for example) or are treated as equivalent IndexedDB keys (for example, since IndexedDB ignores arrays with non-numeric properties and treats them as empty arrays, so any non-numeric arrays are treated as equivalent). This throws an exception if either of the values is not a valid key.
Syntax
var result = indexedDB.cmp(first, second);
Parameters
- first
- The first key to compare.
- second
- The second key to compare.
Return value
An integer that indicates the result of the comparison; the table below lists the possible values and their meanings:
Returned value | Description |
---|---|
-1 | 1st key is less than the 2nd key |
0 | 1st key is equal to the 2nd key |
1 | 1st key is greater than the 2nd key |
Exceptions
This method may raise a DOMException
of the following types:
Attribute | Description |
---|---|
DataError |
One of the supplied keys was not a valid key. |
Example
var a = 1; var b = 2; var result = window.indexedDB.cmp(a, b); console.log( "Comparison results: " + result );
Specifications
Specification | Status | Comment |
---|---|---|
Indexed Database API 2.0 The definition of 'cmp()' in that specification. |
Recommendation | |
Indexed Database API Draft The definition of 'cmp()' in that specification. |
Recommendation |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
cmp | 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 25 | Firefox Android Full support 22 | Opera Android Full support 14 | Safari iOS Full support 8 | Samsung Internet Android Full support 1.5 |
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.)