Date differences in months not working as expected

[aaronazlant]

If I give the library two dates like so:

batchStartTime = new Date("1/2/2015")
batchEndTime = new Date("4/1/2015")

and then do

console.log date.difference(batchStartTime, batchEndTime, "month")

I would expect to see 2 as my result. I do not: I see 3.

[JesperMadsen123]

Just a question:

batchStartTime = new Date("1/2/2015")
batchEndTime = new Date("2/1/2015")

and then do

console.log date.difference(batchStartTime, batchEndTime, "month")

What would be the expected outcome?

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
-**|----|-----|----|-----|----|----|-----|-----|----|----|----
Both january and february are "touched", but their entire period is not within the date range. So is it 0 - month: since no complete month is within the range?
1 - month: since the date range crosses the boundary between january and february?
2 - months: since 2 different months are in the range??

And what if:

batchStartTime = new Date("1/20/2015")
batchEndTime = new Date("3/19/2015")

what would be the expected outcome?
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
---|_|_--|----|-----|----|----|-----|-----|----|----|----

1 - month: since one complete month is within the range?
2 - months: since the date range crosses the boundary between january, february and march?
3 - months: since 3 different months are in the range??