I'm unsure about thenumber | boolean types.
actually thenumber only accepts a certain range (1 through$grid-columns).
and theboolean only acceptstrue.
can that be expressed somehow? I'm new to typescript ;)

at least one ofcontainer oritem has to be set to true.
can that be expressed somehow ?

You can usediscriminated unions/algebraic data types when you want to declare mutually exclusive states.

interfaceFluidGridSharedProps{// all common props go here}interfaceFluidGridContainerPropsextendsFluidGridSharedProps{container:true;item?:false;}interfaceFluidGridItemPropsextendsFluidGridSharedProps{item:true;container?:false;}typeFluidGridProps=FluidGridContainerProps|FluidGridItemProps

Be aware that as a union type rather than an interface there are more limitations placed onFluidGridProps so this approach has drawbacks to consider. One such drawback is that you cannot extend it with a new child interface:

interfaceMyCustomGridPropsextendsFluidGridProps{foo:string;}

^^^ this will throw a compiler error

Instead you must declare a child as a type instead

typeMyCustomGridProps=FluidGridProps&{foo:string}

^^^ this will compile

I haven't reviewed much of the code base to check if this approach is being used for this project but hopefully this answers your question.

I'm unsure ofheight: 100% (and maybealign-items: center) has to go intoFluidGrid.scss forstretch to work properly.

I don't see any difference without it, also it would be an easy change if someone has problems with it :)

these newly added settings duplicate the defaults ofSlider which feels wrong as they might diverge.

works for now, or what would you do instead? 😄