Momentjs seconds from now till a specific hour

moment() is the current time, so if current time is 15:24:32 moment().hour(23) returns 23:24:32. You need to set the minutes and seconds to 0 to get the difference between 15:24:32 and 23:00:00.

This

moment().diff(moment().hour(23).minute(0).second(0), 'seconds');

returns -27328 seconds when the current time is 15:24:32