Exercise: duration

Complete the class Duration, a span of time in seconds. constructor(seconds) stores the number of seconds, and the getter seconds returns it. The static method static fromMinutes(minutes) creates a new Duration object from minutes, and the static method static longest(durations) returns the longest Duration object in the array.

• new Duration(90).seconds → 90
• Duration.fromMinutes(2).seconds → 120
• Duration.longest([new Duration(5), new Duration(30)]).seconds → 30

Constraints: seconds and minutes are non-negative integers; both static methods are called through the class, and instances lack them; durations in the array differ, and an empty array gives null.

Do not add extra imports unless the task says so explicitly.