Run results for: JavaScript spread vs Object.assign performance vs native spread

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:122.0) Gecko/20100101 Firefox/122.0

Browser: Firefox 122

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 9 months ago

Test name	Executions per second
Using the spread operator	1132090.4 Ops/sec
Using Object.assign	12899876.0 Ops/sec
use...	5946794.0 Ops/sec

Tests:

Using the spread operator
"use strict"; function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); if (enumerableOnly) symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; }); keys.push.apply(keys, symbols); } return keys; } function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i] != null ? arguments[i] : {}; if (i % 2) { ownKeys(Object(source), true).forEach(function (key) { _defineProperty(target, key, source[key]); }); } else if (Object.getOwnPropertyDescriptors) { Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)); } else { ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } } return target; } function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; } var firstObject = { sampleData: 'Hello world' }; var secondObject = { moreData: 'foo bar' }; var finalObject = _objectSpread(_objectSpread({}, firstObject), secondObject);
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({}, firstObject, secondObject);
use...
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = {...firstObject, ...secondObject}

Run results for: JavaScript spread vs Object.assign performance vs native spread

Using the spread operator

Using Object.assign

use...