Temporal.Duration.prototype.valueOf()

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The valueOf() method of Temporal.Duration instances throws a TypeError, which prevents Temporal.Duration instances from being implicitly converted to primitives when used in arithmetic or comparison operations.

Syntax

js
valueOf()

Parameters

None.

Return value

None.

Exceptions

TypeError

Always thrown.

Description

Because both primitive conversion and number conversion call valueOf() before toString(), if valueOf() is absent, then an expression like duration1 > duration2 would implicitly compare them as strings, which may have unexpected results such as "PT3S" > "PT1M". By throwing a TypeError, Temporal.Duration instances prevent such implicit conversions. You need to explicitly convert them to numbers using Temporal.Duration.prototype.total(), or use the Temporal.Duration.compare() static method to compare them.

Examples

Arithmetic and comparison operations on Temporal.Duration

All arithmetic and comparison operations on Temporal.Duration instances should use the dedicated methods or convert them to primitives explicitly.

js
const duration1 = Temporal.Duration.from({ seconds: 3 });
const duration2 = Temporal.Duration.from({ minutes: 1 });
duration1 > duration2; // TypeError: can't convert Duration to primitive type
duration1.total("seconds") > duration2.total("seconds"); // false
Temporal.Duration.compare(duration1, duration2); // -1

duration1 + duration2; // TypeError: can't convert Duration to primitive type
duration1.total("seconds") + duration2.total("seconds"); // 63
duration1.add(duration2).toString(); // "PT1M3S"

Specifications

Specification
Temporal proposal
# sec-temporal.duration.prototype.valueof

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
valueOf
Experimental

Legend

Tip: you can click/tap on a cell for more information.

In development. Supported in a pre-release version.
In development. Supported in a pre-release version.
No support
No support
Experimental. Expect behavior to change in the future.
See implementation notes.
User must explicitly enable this feature.

See also