ICSSProp vs. CSSProp? about fable-react HOT 5 CLOSED

Given that IHTMLProp has the same "problem", I was wondering if there was any thought given to removing the interfaces altogether and combining HTMLAttr+DOMAttr+Prop into one big DU so it could also have a homogeneous list type. Maybe other downsides though.

Anyway I made a computation expression to coerce the yielded types so I'm not even that bothered by this anymore. It's more syntax up front but better than casting every yield IMO. It's a suitable workaround for me so it's fine if we want to close this and not mess with it for now.

type CompatibleList<'a>() =
  member x.Yield(item:'a) : 'a list = List.singleton item
  member x.YieldFrom(expr:'a list) : 'a list = expr
  member x.Combine(left:'a list, right:'a list) : 'a list = List.append left right
  member x.Delay(fn:unit -> 'a list) : 'a list = fn()
  member x.Zero() : 'a list = List.empty<'a>
  member x.For(expr:'b seq, fn:'b -> 'a list) : 'a list = expr |> Seq.toList |> List.collect fn

let cssprops = CompatibleList<ICSSProp>()
let htmlprops = CompatibleList<IHTMLProp>()

let view model =
  div <| htmlprops {
    yield Id "view"
    yield Style <| cssprops {
      yield Margin 0
      yield Padding 0
    }
  } <| [
    span [] [ str "hello" ]
  ]

from fable-react.

There MUST be a reason... I just don't remember what it is, let me check 😅 BTW, you can use upcast instead of unbox, which is type safe and it'll be also erased in JS code. But I acknowledge it's still annoying.

from fable-react.

Ah, thanks for type-safe upcast tip, that's a little better since I'm adding the yields anyway and don't have to repeat the type. Plus it also works with e.g. IHTMLProp list. 👍 I guess ICSSProp was probably modeled like IHTMLProp but ended up with only one implementer.

from fable-react.

Your guess is probably right. I had a look at the source and I don't remember why I exactly did it like that 😅

Maybe it was a simpler way to solve the top-down order in F#, but we can use module rec or and for that. I'm ok with removing ICSSProp 👍

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IIRC DOMAttr and HTMLAttr had to be separated because SVG elements accept the former but not the latter.

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