Temporal.Instant.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.Instant instances throws a TypeError, which prevents Temporal.Instant instances from being implicitly converted to primitives when used in arithmetic or comparison operations.

Syntax

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 instant1 > instant2 would implicitly compare them as strings, which may have unexpected results. By throwing a TypeError, Temporal.Instant instances prevent such implicit conversions. You need to explicitly convert them to numbers using Temporal.Instant.prototype.epochNanoseconds, or use the Temporal.Instant.compare() static method to compare them.

Examples

Arithmetic and comparison operations on Temporal.Instant

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

const instant1 = Temporal.Instant.fromEpochMilliseconds(0);
const instant2 = Temporal.Instant.fromEpochMilliseconds(1000);
instant1 > instant2; // TypeError: can't convert Instant to primitive type
instant1.epochNanoseconds > instant2.epochNanoseconds; // false
Temporal.Instant.compare(instant1, instant2); // -1

instant2 - instant1; // TypeError: can't convert Instant to primitive type
instant2.since(instant1).toString(); // "PT1S"

Specifications

Specification
Temporal # sec-temporal.instant.prototype.valueof

Browser compatibility

	Desktop					Mobile						Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	Deno	Node.js
`valueOf`	No	No	139	No	preview	No	139	No	No	No	No	1.40	No