If payload size is the top concern you shouldn't be using Moment either though. Luxon and DayJS are both considerably smaller (their uncompressed size is about what Moment's compressed size is) and the date-fns library is much, much smaller and also tree-shakeable. Moment also performs at or near the bottom of all available options if speed is a concern. Other than reflexive popularity or the cost already being paid there's not really a good reason to use it anymore.