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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.


var result = indexedDB.cmp(first, second);


The first key to compare.
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


This method may raise a DOMException of the following types:

Attribute Description
DataError One of the supplied keys was not a valid key.


var a = 1;
var b = 2;
var result = window.indexedDB.cmp(a, b);
console.log( "Comparison results: " + result );


Specification Status Comment
Indexed Database API
The definition of 'cmp()' in that specification.
Indexed Database API 2.0
The definition of 'cmp()' in that specification.

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 23webkit
24 (unprefixed)
(Yes) 10 moz
16.0 (16.0)
10, partial 15 7.1
Available in workers (Yes) (Yes) 37.0 (37.0) (Yes) (Yes) 10
Indexed Database 2.0 58 ? ? ? 45 ?
Feature Android Webview Chrome for Android Edge Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) 22.0 (22.0) 1.0.1 10 22 8
Available in workers (Yes) (Yes) (Yes) 37.0 (37.0) (Yes) (Yes) (Yes) 10
Indexed Database 2.0 58 58 ? ? ? ? 45 ?

See also

Document Tags and Contributors

 Last updated by: jpmedley,