Run results for: JSON.stringify vs structuredClone vs simple deepCopyObject

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser: Chrome 126

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
JSON.stringify	1497551.0 Ops/sec
structuredClone	856547.8 Ops/sec
deepCopyObject	1326036.0 Ops/sec

Script Preparation code:

var deepCopyObject = (inObject) => {
  if (inObject instanceof Date) return inObject

  if (inObject instanceof Set) return new Set(inObject)

  if (inObject instanceof Map) return new Map(inObject)

  if (typeof inObject !== 'object' || inObject === null) {
    return inObject // Return the value if inObject is not an object
  }

  // Create an array or object to hold the values
  const outObject = Array.isArray(inObject) ? [] : {}

  Object.keys(inObject).forEach((key) => {
    const value = inObject[key]

    // Recursively (deep) copy for nested objects, including arrays
    outObject[key] = typeof value === 'object' && value !== null ? deepCopyObject(value) : value
  })

  return outObject
}


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);
deepCopyObject
myCopy = deepCopyObject(MyObject);