It’s just a matter of RTFM I guess, the a.add() method returns “a” so that you can chain methods on the same object without creating a new object on every metho

It’s just a matter of RTFM I guess, the a.add() method returns “a” so that you can chain methods on the same object without creating a new object on every method call. Else: a.add(1, ‘second’).add(1, ‘day’).subtract(2, ‘minute’) would create 3 more objects that are not needed. Creating a new moment object is expensive, it happened to me to work with a lib that grew exponentially slow when using above N dates because they where constantly recreating moments instead of using them wisely so creating a new one on every operation would be quite bad. That’s why the method .clone() exists, so you can declare that explicitly: const a = moment() const b = a.clone().add(1, ‘second’) PS: don’t take RTFM as an offense, I just happen to like it a lot and we use it frequently at work, I don’t mean to be disrespectful towards you :)