fix(datepicker): min-date/max-date: parse fix for literals

[davious]

fixes #3437

original plunker, with pr code: http://plnkr.co/edit/jsfOVBZj51yajpZYkC9N?p=preview
maintainer plunker, with pr code: http://plnkr.co/edit/buQXUxndajMYFOZorzq9?p=preview

[wesleycho]

Fix formatting - an easy way to see what is off is to rebase off of current master, run npm install, and run grunt eslint.

[wesleycho]

What happens when isNaN(tryDate) is true?

[davious]

undefined gets set.... this is to cover for an invalid attribute; example: a scope variable that doesn't exist.

[davious]

Not sure what formatting needs fixing. I rebased and ran grunt eslint: Done, without errors

[wesleycho]

As a rule of thumb, the code should look like the surrounding code - the whitespace differences are pretty stark in this case, or lack of whitespace.

[wesleycho]

Thinking about this problem for a bit, I am not sure we want to support this date format in the long run - it would be much better if it required a date object from the user's side as a breaking change, which would prevent the timezone issue, and allow the user the flexibility to specify the timezone of the min date.

[wesleycho]

One can get the information from the date via this mechanism:

var year = date.getFullYear(),
  month = date.getMonth(),
  day = date.getDate();

[davious]

the reason I'm using the toISOString() (I plan to switch to equivalent toJSON() next commit) is to get the UTC version of the date, otherwise there is the same timezone issue we are seeing in #3437... the date for EST looks something like 9PM the day before, and the date becomes off by 1.

[wesleycho]

As stated prior, one can get the information from the date via this mechanism:

var year = date.getFullYear(),
  month = date.getMonth(),
  day = date.getDate();

This is a better way of getting the date information

[davious]

Changed the code to simply parse dates:

• We now expect literal min-date and max-date to match the displayFormat; otherwise, it will not work at all
• If they want to use an alternate format, they can indicate it in alt-input-formats

This fixes the underlying problem in issue #3437, which is that javascript parses yyyy-MM-dd as GMT; see #3437 (comment)

[davious]

Just realized that the concepts of display format and alt-input-formats does not exist for the datepicker itself. So, this would still be an issue for the datepicker proper; and, the different behavior of min-date/max-date would be confusing.

[davious]

OK. Switched to using dateFilter to feed new Date for these literal cases.

[davious]

@wesleycho would you re-review?

[wesleycho]

Only thing I hesitate on is the assumption of the medium format in the dateFilter usage - I guess I'm ok with that, but it needs to be mentioned in the documentation.

[davious]

The medium format is an internal format picked "at random"... Any format that indicates all the possible date information would do the trick. It doesn't impact the parse work.

[wesleycho]

Guess I'm fine with it - LGTM then