JavaScript PlainDate valueOf()
Example
const date = Temporal.PlainDate.from("2026-05-17");
try {
let text = date.valueOf());
} catch (err) {
text = err;
}
Try it Yourself »
TypeError: Cannot convert Temporal.PlainDate to a number.
Description
The valueOf() method throws a TypeError.
This prevents temporal instances from being implicitly converted to primitives.
The valueOf() method does not change the original instant.
Note
Temporal objects do not allow implicit conversion to numbers.
This prevents accidental errors when working with dates and times.
Syntax
plaindate.valueOf()
Parameters
| NONE |
Return Value
| NONE |
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 and Safari Support
Opera support will probably appear 1-3 browser cycles after Chromium, which often means a few months later.
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:
<script
src="https://cdn.jsdelivr.net/npm/@js-temporal/polyfill/dist/index.umd.js">
</script>
