[QDateTime] Month 'forward' button has undesirable behaviour

[dsl101]

Software version

Quasar: 0.14
Browsers: Vivaldi 1.11.894.3 (Official Build) (64-bit)

What did you get as the error?

When a date picker is opened on the 31st of a month which precedes a month with only 30 days (e.g. 2017-08-31), clicking the right-arrow to move to the next month causes a jump by 2 months.

What were you expecting?

I would expect a more natural behaviour would be to jump to the last day of the next month (i.e. in this case 2017-09-30)

This problem seems to stem from the javascript implementation of setMonth(). Try this in a browser console:

d = new Date('2017-08-31')
d.getMonth()  // 7
d.setMonth(8)
d.getMonth()  // 9

I'm working on a PR for fixing this, but it's not obvious—I'm not sure quite how the setMonth() function in InlineDatetimeMat.vue works—this.month is 1–based, whereas the javascript Date().setMonth() is 0–based. Need to look closer and out of time right now.

[dsl101]

See PR #850 - I think this solves the problem both forward and backwards.

[rstoenescu]

Decided to go with another approach, fixing some "date" utils as well.
Fix is available in latest edge version and future v0.15.