MeasureThat.net

Run results for: Spread vs Object.assign mutate

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Run details:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36
Chrome 131
Mac OS X 10.15.7
Desktop
4 months ago
Test name Executions per second
Object.assign two objects 47612.7 Ops/sec
Spread two objects 44886.8 Ops/sec
Script Preparation code:
​x
 
window.object1 = {};
window.object2 = {};
​
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);
Tests:

  • Object.assign two objects

     
    let object7 = Object.assign({}, object1);
    object7 = Object.assign(object7, object2);

  • Spread two objects

     
    const object7 = Object.assign({}, object1);
    const object8 = {...object7, ...object2};