Add support for navigating with numberOfMonths

[zaygraveyard]

I'm using this component with numberOfMonths = 4 and I need the navigation between months to be more like changing the page of months. E.g:

The visible months can be [1, 2, 3, 4] or [5, 6, 7, 8] or [9, 10, 11, 12]
So the visible months can never be [3, 4, 5, 6] for example.

I'm not setting the fromMonth and toMonth props so I can never run into the case where some of the months are not allowed.
But I understand that it can problematic.

One solution would be to only render the allowed months. E.g:
If the fromMonth = 2 and toMonth= 3 then we render [2, 3]
If the fromMonth = 2 and toMonth= 5 then we render [2, 3, 4], [5]

An other solution would be to say that the only change to the current behavior is that showNextMonth() and showPreviousMonth() will change the currentMonth by numberOfMonths instead of 1.

I would be happy to create a PR

[gpbl]

An other solution would be to say that the only change to the current behavior is that showNextMonth() and showPreviousMonth() will change the currentMonth by numberOfMonths instead of 1.

I like this idea. As default it should work as it does now (e.g. skipping only one month), but we could add a new prop to change the behavior of showNextMonth and showPreviousMonth. How could we call this new prop? pagedNavigation?

[zaygraveyard]

Thank you for the fast reply.
A boolean pagedNavigation looks good to me.

[gpbl]

Would you send a PR? :)

[zaygraveyard]

Sure, I'll do that ASAP

[zaygraveyard]

I just noticed there's still this case:
numberOfMonths = 4
fromMonth = 3
currentMonth = 5
And we call showPreviousMonth()

What is the expected behavior?

[gpbl]

Actually the wrong value there is in currentMonth, that should never be 5. Is the currentMonth in this case coming from the initialMonth prop, or does it take this value after navigating the months? Need to check it out.

[zaygraveyard]

It's coming from the initialMonth prop.

[gpbl]

Thanks, so we have two approach here:

• the developer is responsible to check that initialMonth has the correct value
• we add some logic in getStateFromProps to make currentMonth match the right month

We had a similar issue where [we preferred] the first option, but I'm open to change my mind about it!

[zaygraveyard]

I think it's the developer's responsibility, but we should also have a reasonable default behavior.
Something along the lines of:

getStateFromProps = props => {
  const initialMonth = Helpers.startOfMonth(props.initialMonth);
  let currentMonth = initialMonth;

  if (
    props.pagedNavigation    &&
    props.numberOfMonths > 1 &&
    props.fromMonth
  ) {
    const diffInMonths = Helpers.diffInMonths(currentMonth, fromMonth);

    currentMonth = Helpers.addMonths(
      fromMonth,
      Math.floor(diffInMonths / props.numberOfMonths) * props.numberOfMonths
    );
  }
  return {currentMonth};
}

What do you think? Do I add it to the PR?

[gpbl]

@zaygraveyard could you send the change above in an another PR? I'd prefer to deal with one issue at time (and we need tests for it as well) Thanks a lot!

[zaygraveyard]

Yeah sure 😄

[zaygraveyard]

The code for the second issue is ready, but it requires that #197 gets merged.
I'll send a PR as soon as the first one is merged.