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

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.

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

Browser compatibility

See also

• Temporal.PlainDateTime
• Temporal.PlainDateTime.prototype.toString()
• Temporal.PlainDateTime.prototype.toJSON()
• Temporal.PlainDateTime.prototype.toLocaleString()