momentjs - moment.js - Convert short month to long month? -

given following short month:

var shortmonth = 'jan'; 

how can convert long month format january using moment.js?

moment().format('mmmm'); gives long month format of current month, can't seem find way convert short month long month.

something moment().format(shortmonth,'mmmm'); example doesn't work.

any idea how work?

try this:

moment('jan', 'mmm').format('mmmm')