Run results for: Manual clone versus prototype extend

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36

Browser: Chrome 53

Operating system: Mac OS X 10.10.5

Device Platform: Other

Date tested: 8 years ago

Test name	Executions per second
Manual clone	9802892.0 Ops/sec
Prototype	1620940.2 Ops/sec

Script Preparation code:

var MergeState = (function () {
        function MergeState() {
            this.writeVersion = 0;
            this.deepInspect = false;
        }
        MergeState.prototype.derive1 = function () {
            var ret = new MergeState();
            ret.writeVersion = this.writeVersion;
            ret.deepInspect = this.deepInspect;
            return ret;
        };
        MergeState.prototype.derive2 = function () {
            var ret = {};
            Object.setPrototypeOf(ret, this);
            return ret;
        };
        return MergeState;
    }());

var base = new MergeState();

Tests:

Manual clone
var der = base.derive1();
Prototype
var der = base.derive2();