Throw RangeError if dateStyle/timeStyle is attempted with required equals to the other.

[zbraniecki]

Fixes the remaining piece of #35.

[zbraniecki]

@littledan, @anba - does it look good to you?

[zbraniecki]

Depending on the resolution of #46 I may shift it to TypeError prior or after landing.

[anba]

The possible values for required and defaults are:

• InitializeDateTimeFormat
  • required: any
  • defaults: date
• toLocaleString
  • required: any
  • required: all
• toLocaleDateString
  • required: date
  • required: date
• toLocaleTimeString
  • required: time
  • required: time

And we only want to throw for:

• toLocaleDateString and timeStyle is present.
• toLocaleTimeString and dateStyle is present.

So I think the error conditions should be:

• If required is "date" and timeStyle is not undefined, throw a Range/TypeError exception.
• If required is "time" and dateStyle is not undefined, throw a Range/TypeError exception.

[zbraniecki]

Ah, right! We don't want to throw on required = "any". I updated the patch.

@anba can you take another look for r?

[anba]

LGTM!

Can you add the two new steps below the existing two Get calls for date/timeStyle, instead of moving all steps before If required is "date" or "any", then? That way the Get calls in ToDateTimeOptions for the individual properties will be executed in the same order as in InitializeDateTimeFormat.