JavaScript PlainDate add()
Example
const date1 = Temporal.PlainDate.from("2026-05-17");
const date2 = date1.add({ months:1, days:10 });
Try it Yourself »
Description
The add() method returns a new plain date with a duration added.
The add() method does not change the original instant.
Syntax
plaindate.add(duration)
Parameters
| Parameter | Description |
| duration | The duration to be added. |
Return Value
| Type | Description |
| Object | A new plain date with the duration added. |
Browser Support
Temporal is a major update to the JavaScript standard (TC39).
It is currently fully supported in Chrome, Edge, and Firefox, and is expected to reach full availability across browsers before the summer of 2026.
| Chrome 144 |
Edge 144 |
Firefox 139 |
Safari |
Opera |
| Jan 2026 | Jan 2026 | May 2025 | 🚫 | 🚫 |
Opera Support
Opera support will probably appear 1-3 browser cycles after Chromium, which often means a few months later.
Safari Support
The implementation is actively in development and can be tested today in Safari Technology Preview by enabling the --use-temporal runtime flag.
Polyfill
Until Opera and Safari supports Temporal natively, you can use the official polyfill.
Example
<script
src="https://cdn.jsdelivr.net/npm/@js-temporal/polyfill/dist/index.umd.js">
</script>
<script>
// Now you can use Temporal
const today = Temporal.Now.plainDateISO();
</script>
