IDBFactory: cmp() method
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
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.
Syntax
cmp(first, second)
Parameters
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
DataErrorDOMException-
Thrown if one of the supplied keys was not a valid key.
Examples
const a = 1;
const b = 2;
const result = window.indexedDB.cmp(a, b);
console.log(`Comparison results: ${result}`);
Specifications
| Specification |
|---|
| Indexed Database API 3.0 # ref-for-dom-idbfactory-cmp① |
Browser compatibility
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
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 the example live).