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: This feature is available in Web Workers.
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 2.0The definition of 'cmp()' in that specification. | Recommendation | |
Indexed Database API DraftThe definition of 'cmp()' in that specification. | Recommendation |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
cmp
|
Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Implemented with the vendor prefix: webkit |
Edge
Full support 12 |
Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Implemented with the vendor prefix: moz |
IE
Partial support 10 |
Opera
Full support 15 |
Safari
Full support 7 |
WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Implemented with the vendor prefix: webkit |
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 ([[../../../../../../../mdn.github.io/to-do-notifications/index|view example live]].)
IDBFactory.cmp() by Mozilla Contributors is licensed under CC-BY-SA 2.5.