Run results for: Spread vs Object.assign

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36

Browser: Chrome 132

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Object.assign two objects	37053.3 Ops/sec
Spread two objects	48834.4 Ops/sec
Object.assign three objects	20150.8 Ops/sec
Spread three objects	31536.0 Ops/sec
Object.assign four objects	17089.0 Ops/sec
Spread four objects	22891.9 Ops/sec
Object.assign five objects	9927.3 Ops/sec
Spread five objects	17669.9 Ops/sec
Object.assign six objects	7662.6 Ops/sec
Spread six objects	13612.7 Ops/sec

Script Preparation code:

window.object1 = {};
window.object2 = {};
window.object3 = {};
window.object4 = {};
window.object5 = {};
window.object6 = {};

function makeid() {
  var text = "";
  var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

  for (var i = 0; i < 5; i++)
    text += possible.charAt(Math.floor(Math.random() * possible.length));

  return text;
};

function populate(object) {
  for (let i = 0; i < 100; i++) {
    object[makeid()] = makeid();
  }
};

populate(object1);
populate(object2);
populate(object3);
populate(object4);
populate(object5);
populate(object6);

Tests:

Object.assign two objects
const object7 = Object.assign({}, object1, object2);
Spread two objects
const object7 = {...object1, ...object2};
Object.assign three objects
const object7 = Object.assign({}, object1, object2, object3);
Spread three objects
const object7 = {...object1, ...object2, ...object3};
Object.assign four objects
const object7 = Object.assign({}, object1, object2, object3, object4);
Spread four objects
const object7 = {...object1, ...object2, ...object3, ...object4};
Object.assign five objects
const object7 = Object.assign({}, object1, object2, object3, object4, object5);
Spread five objects
const object7 = {...object1, ...object2, ...object3, ...object4, ...object5};
Object.assign six objects
const object7 = Object.assign({}, object1, object2, object3, object4, object5, object6);
Spread six objects
const object7 = {...object1, ...object2, ...object3, ...object4, ...object5, ...object6};

Run results for: Spread vs Object.assign

Object.assign two objects

Spread two objects

Object.assign three objects

Spread three objects

Object.assign four objects

Spread four objects

Object.assign five objects

Spread five objects

Object.assign six objects

Spread six objects