Temporal.PlainDateTime.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.PlainDateTime instances throws a TypeError, which prevents Temporal.PlainDateTime 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 dateTime1 > dateTime2 would implicitly compare them as strings, which may have unexpected results. By throwing a TypeError, Temporal.PlainDateTime instances prevent such implicit conversions. You need to explicitly convert them to strings using Temporal.PlainDateTime.prototype.toString(), or use the Temporal.PlainDateTime.compare() static method to compare them.

Examples

Arithmetic and comparison operations on Temporal.PlainDateTime

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

js
const dt1 = Temporal.PlainDateTime.from("2022-01-01T00:00:00");
const dt2 = Temporal.PlainDateTime.from("2022-07-01T00:00:00");
dt1 > dt2; // TypeError: can't convert PlainDateTime to primitive type
Temporal.PlainDateTime.compare(dt1, dt2); // -1

dt2 - dt1; // TypeError: can't convert PlainDateTime to primitive type
dt2.since(dt1).toString(); // "P181D"

Specifications

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

Browser compatibility

BCD tables only load in the browser

See also