Benchmark: create a specific Date object vs modifying an existing one

HTML Preparation code:

<div id="date.create"></div>
<div id="date.set"></div>
<div id="date.setTime"></div>

Script Preparation code:

var create;
var elCreate = document.getElementById('date.create');

var set = new Date(0);
var elSet = document.getElementById('date.set');

var time = new Date(1999, 1, 28).getTime();
var setTime = new Date(0);
var elSetTime = document.getElementById('date.setTime');

Tests:

new Date
create = new Date(1999, 1, 28); elCreate.innerText = create;
modify Date
set.setDate(1); set.setFullYear(1999); set.setMonth(1); set.setDate(28); set.setHours(0); set.setMinutes(0); set.setSeconds(0); set.setMilliseconds(0); elSet.innerText = set;
setTime
setTime.setTime(time); elSetTime.innerText = setTime;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Date
modify Date
setTime

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:151.0) Gecko/20100101 Firefox/151.0

Browser/OS: Firefox 151 on Mac OS X 10.15

View result in a separate tab

setTime

1.3M/s

new Date

1.3M/s

modify Date

1.0M/s

View exact numbers

Test name	Executions per second
✓ setTime	1,305,703 Ops/sec
new Date	1,286,514 Ops/sec
modify Date	1,000,299 Ops/sec

create a specific Date object vs modifying an existing one (version: 4)

How expensive is creation of a Date instance.

Comparing performance of: `new Date vs modify Date vs setTime`

Created: 2 months ago by: Registered User

Go to the latest result

new Date

modify Date

setTime

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

create a specific Date object vs modifying an existing one (version: 4)

How expensive is creation of a Date instance.

Comparing performance of: new Date vs modify Date vs setTime

Created: 2 months ago by: Registered User

Go to the latest result

new Date

modify Date

setTime

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `new Date vs modify Date vs setTime`