Below is the functionality needed for the Duration component.

• 7.3.3 get Temporal.Duration.prototype.years
• 7.3.4 get Temporal.Duration.prototype.months
• 7.3.5 get Temporal.Duration.prototype.weeks
• 7.3.6 get Temporal.Duration.prototype.days
• 7.3.7 get Temporal.Duration.prototype.hours
• 7.3.8 get Temporal.Duration.prototype.minutes
• 7.3.9 get Temporal.Duration.prototype.seconds
• 7.3.10 get Temporal.Duration.prototype.milliseconds
• 7.3.11 get Temporal.Duration.prototype.microseconds
• 7.3.12 get Temporal.Duration.prototype.nanoseconds
• 7.3.13 get Temporal.Duration.prototype.sign
• 7.3.14 get Temporal.Duration.prototype.blank (implemented as is_zero)
• 7.3.15 Temporal.Duration.prototype.with ( temporalDurationLike )
• 7.3.16 Temporal.Duration.prototype.negated ( )
• 7.3.17 Temporal.Duration.prototype.abs ( )
• 7.3.18 Temporal.Duration.prototype.add ( other [ , options ] )
• 7.3.19 Temporal.Duration.prototype.subtract ( other [ , options ] )
• 7.3.20 Temporal.Duration.prototype.round ( roundTo )
• 7.3.21 Temporal.Duration.prototype.total ( totalOf )
• 7.3.22 Temporal.Duration.prototype.toString ( [ options ] )
• 7.3.23 Temporal.Duration.prototype.toJSON ( )
• 7.3.24 Temporal.Duration.prototype.toLocaleString ( [ locales [ , options ] ] ) (not yet implementable - needs icu_duration if it were to exist)
• 7.3.25 Temporal.Duration.prototype.valueOf ( )