Run results for: JSON.stringify vs structuredClone vs spread vs Object.assign()

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:133.0) Gecko/20100101 Firefox/133.0

Browser: Firefox 133

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Object.assign

39.6M/s

spread

18.0M/s

JSON.stringify

1.1M/s

structuredClone

708K/s

View exact numbers

Test name	Executions per second
✓ Object.assign	39,633,904 Ops/sec
spread	17,978,494 Ops/sec
JSON.stringify	1,104,997 Ops/sec
structuredClone	708,205 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);
spread
myCopy = {...MyObject};
Object.assign
myCopy = Object.assign({}, MyObject);