Run results for: object creation: object mutation vs hidden class vs combined vs field declaration

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/116.0

Browser: Firefox 116

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
With mutation	340.5 Ops/sec
constructor	556.4 Ops/sec

Tests:

With mutation
class SomeClass { one = "" two = 1 } for (var i = 0; i < 10_000; i++) { const obj = new SomeClass() obj.two = 2 }
constructor
class SomeClass { one = "" constructor(two) { this.two = two } } for (var i = 0; i < 10_000; i++) { const obj = new SomeClass(2) }
with constructor and mutation
class SomeClass { one = "" two = 1 constructor(two) { this.two = two } } for (var i = 0; i < 10_000; i++) { const obj = new SomeClass(2) }
declaration and constructor
class SomeClass { one constructor(one) { this.one = one } } for (var i = 0; i < 10_000; i++) { const obj = new SomeClass(2) }