Run results for: Object.assign vs iteration performance, more props (Grammarly Focal)

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.80 Safari/537.36

Browser: Chrome 98

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Iteration with blank object	834616.8 Ops/sec
Object.assign with blank object	2201569.0 Ops/sec
Iteration with created object	632789.6 Ops/sec
Object.assign with created object	1277970.0 Ops/sec
Iteration with blank object and prototype	629423.2 Ops/sec
Object.assign with blank object and prototype	1186001.0 Ops/sec
Iteration with blank object and prototype prop	756322.3 Ops/sec
Object.assign with blank object and prototype prop	1797884.0 Ops/sec

Script Preparation code:

class Thing {
    constructor() {
        this.a1 = Math.random();
        this.a2 = Math.random();
        this.a3 = Math.random();
        this.a4 = Math.random();
        this.a5 = Math.random();
        this.a6 = Math.random();
        this.a7 = Math.random();
        this.a8 = Math.random();
        this.a9 = Math.random();
        this.aa = Math.random();
        this.ab = Math.random();
    }
}

var r = new Thing();

Tests:

Iteration with blank object
var copy = {}; for(const prop in r) copy[prop] = r[prop];
Object.assign with blank object
var copy = {}; Object.assign(copy, r);
Iteration with created object
var copy = Object.create(Object.getPrototypeOf(r)); for(const prop in r) copy[prop] = r[prop];
Object.assign with created object
var copy = Object.create(Object.getPrototypeOf(r)); Object.assign(copy, r);
Iteration with blank object and prototype
var copy = {}; Object.setPrototypeOf(copy, Object.getPrototypeOf(r)); for(const prop in r) copy[prop] = r[prop];
Object.assign with blank object and prototype
var copy = {}; Object.setPrototypeOf(copy, Object.getPrototypeOf(r)); Object.assign(copy, r);
Iteration with blank object and prototype prop
var copy = {}; copy.__proto__ = r.__proto__; for(const prop in r) copy[prop] = r[prop];
Object.assign with blank object and prototype prop
var copy = {}; copy.__proto__ = r.__proto__; Object.assign(copy, r);

Run results for: Object.assign vs iteration performance, more props (Grammarly Focal)

Iteration with blank object

Object.assign with blank object

Iteration with created object

Object.assign with created object

Iteration with blank object and prototype

Object.assign with blank object and prototype

Iteration with blank object and prototype prop

Object.assign with blank object and prototype prop