[feature] Prevent toISOString converting to UTC (issue #1751)

[ashsearle]

A minimal effort to allow users to opt-out of UTC conversion when calling toISOString():

moment().toISOString();
moment().toISOString({ utc: false });

Example while running in Europe/London timezone:

moment('2017-07-01').toISOString(); // 2017-06-30T23:00:00.000Z
moment('2017-07-01').toISOString({ utc: false }); // 2017-07-01T00:00:00.000+01:00

The PR preserves existing behaviour of converting to UTC by default.

[icambron]

I love the option object pattern, but it's not how Moment works stylistically. Maybe just a boolean arg?

[ashsearle]

Sure, I'm happy to change. Which way round do you want it: should toISOString() be the same as toISOString(true) or toISOString(false)?

I guess a single argument is also easy enough to expand in future too: e.g. by passing in 60 or +01:00 to get an ISO string in the specified offset...?

[icambron]

Right, something like that. Honestly, the object is better, but when in Rome...

On defaults, I think it's more intuitive to default to false.

[ashsearle]

Updated...

Is the function parameter name OK?

[icambron]

The name seems fine