starting from moment 2.10.5 you can do:
moment(/*your date*/).calendar(null,{
lastDay : '[Yesterday]',
sameDay : '[Today]',
nextDay : '[Tomorrow]',
lastWeek : '[last] dddd',
nextWeek : 'dddd',
sameElse : 'L'
})
see: http://momentjs.com/docs/#/displaying/calendar-time/