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

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.

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

Browser compatibility

See also

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