Run results for: JSON.stringify vs structuredClone vs custom

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:141.0) Gecko/20100101 Firefox/141.0

Browser: Firefox 141

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

deepClone

6.9M/s

structuredClone

1.4M/s

JSON.stringify

1.3M/s

View exact numbers

Test name	Executions per second
✓ deepClone	6,888,242 Ops/sec
structuredClone	1,438,812 Ops/sec
JSON.stringify	1,342,952 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;

function deepClone(obj) {
  if (obj === null || typeof obj !== "object") return obj;

  const copy = Array.isArray(obj) ? [] : {};

  for (const key in obj) {
    if (Object.prototype.hasOwnProperty.call(obj, key)) {
      copy[key] = deepClone(obj[key]);
    }
  }

  return copy;
}

Tests:

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