IDBFactory: cmp() method

Note: This feature is available in Web Workers.

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.


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


DataError DOMException

Thrown if one of the supplied keys was not a valid key.


const a = 1;
const b = 2;
const result = window.indexedDB.cmp(a, b);
console.log(`Comparison results: ${result}`);


Indexed Database API 3.0
# ref-for-dom-idbfactory-cmp①

Browser compatibility

BCD tables only load in the browser

See also