add function not worked properly

[omidgharib]

add functionlity
moment(monthEnd).add(1, "jMonth")
Expected behavior
I expected that line of code give me the end date of next month
PS: monthEnd is end date of the current month
i have to change it to moment(monthEnd).subtract(1, "jMonth").endOf("jMonth") to be worked.

[omidgharib]

برای مثال وقتی monthEnd آخر ماه اسفند 1399 هستش و یک ماه به ان اضافه می کنید میشه 29 فروزدین 1400 (در صورتی که بهتر هست بشود 31 فروردین)

[fingerpich]

so moment(monthMiddle).add(1, 'month') should be the middle of next month?
Does the moment.js doing what you expect?