Add TypeScript types

[yxliang01]

Would be great if TypeScript types can be added.

[stale]

Is this still relevant? If so, what is blocking it? Is there anything you can do to help move it forward?

[Laurianti]

The support was created but not merged, why?

The support was done in this PRs
#15
#20

[Laurianti]

Similar issues:
#10
#22