Proposal: utilize date-io to create adapters for svelte-gantt

[AndreyYolkin]

At the current moment, svelte-gantt only supports JSDate/moment adapters. However, there are more date-managing libs nowadays and adapters can reduce output size reusing them instead of JSDate adapter. To make writing adapters easier, I suggest to look at https://github.com/dmtrKovalenko/date-io and add support for other libs while using consistent api.

If you find it reasonable, I'm willing to help with the implementation

[AndreyYolkin]

If you want to keep project dependency-free, I also respect this decision, then I want to help with other libs (luxon, dayjs, dayfns) adapters

[ANovokmet]

Hi, of course! Currently adapters are used for formatting (displaying labels) and rounding (needed when dropping a task), but otherwise dates are used as numbers (UNIX timestamps) which I am happy with. The rounding was an issue when we ditched moment.js and people started reporting incorrect times when in some time zones (eg. UTC+5:30). Since svelte-gantt is from recently a monorepo you could create a new package eg. svelte-gantt/date-io.

Another thing I would like to have is cleaning up the default (JS Date) adapter, so that maybe the roundTo function is more robust.