Run results for: JSON.stringify vs structuredClone

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 19_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.0 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 26

Operating system: iOS 19.0

Device Platform: Mobile

Date tested: one year ago

JSON.stringify

2.8M/s

structuredClone

895K/s

View exact numbers

Test name	Executions per second
✓ JSON.stringify	2,753,078 Ops/sec
structuredClone	894,866 Ops/sec

Script Preparation code:

var MyObject = {
  description: 'Creates a deep copy of source, which should be an object or an array.',
  myNumber: 123456789,
  myBoolean: true,
  jayson: {
    stringify: 'JSON.stringify() method converts a JavaScript value to a JSON string....',
    parse: 'JSON.parse() method parses a JSON string...'
  }
};

var myCopy = null;

Tests:

JSON.stringify
myCopy = JSON.parse(JSON.stringify(MyObject));
structuredClone
myCopy = structuredClone(MyObject);