Temporal.PlainDateTime.prototype.valueOf()

The valueOf() method of {{jsxref("Temporal.PlainDateTime")}} instances throws a {{jsxref("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#

• {{jsxref("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 {{jsxref("Temporal/PlainDateTime/toString", "Temporal.PlainDateTime.prototype.toString()")}}, or use the {{jsxref("Temporal/PlainDateTime/compare", "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#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("Temporal.PlainDateTime")}}
• {{jsxref("Temporal/PlainDateTime/toString", "Temporal.PlainDateTime.prototype.toString()")}}
• {{jsxref("Temporal/PlainDateTime/toJSON", "Temporal.PlainDateTime.prototype.toJSON()")}}
• {{jsxref("Temporal/PlainDateTime/toLocaleString", "Temporal.PlainDateTime.prototype.toLocaleString()")}}