Run results for: Object addition - checking for existence - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36

Browser: Chrome 97

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
Set New, No Check	14902280.0 Ops/sec
Set New, Check	3920521.5 Ops/sec
Set Existing, No Check	14100330.0 Ops/sec
Set Existing, Check	3964788.5 Ops/sec

Script Preparation code:

var obj = {
    "one": null,
    "two": null,
}

Tests:

Set New, No Check
obj["three"] = null;
Set New, Check
if (obj["three"] !== undefined) { obj["three"] = null; }
Set Existing, No Check
obj["two"] = null;
Set Existing, Check
if (obj["two"] !== undefined) { obj["two"] = null; }