Type inference

[fable-compiler]

Type inference

[MangelMaxime]

In my Helpers, I choose to mimic the class implementation with different modules:

module Marker =

    let addTo (map: L.Map) (marker: L.Marker) =
        marker.addTo(!^map)
        |> unbox<L.Marker>

    let on (eventType: string) callback (marker: L.Marker) =
        marker.on(eventType, callback)
        |> unbox<L.Marker>

module Polygon =

    let addTo o (polygon : L.Polygon) =
        polygon.addTo o
        |> unbox<L.Polygon>

    let on (eventType, cb) (polygon : L.Polygon) =
        polygon.on(eventType, cb)
        |> unbox<L.Polygon>

So yes, that can require more work, but as these are classes from the bindings it's more easier for the User to use the binding in a functional way.

In your case, I think the backTo is good enough for the sample usage. Will see if for a bigger app it's works too.

[whitetigle]

Thanks for sharing @MangelMaxime I like this way of doing it 👍

[alfonsogarciacaro]

@whitetigle To make this more generic and not restrict it to ExtendedSprite you can use generic constraints:

let attachEvent<'T when 'T :> PIXI.Sprite> (ev: PixiEvent) (handler: EventHandler) (sprite: 'T) =
  sprite.on(string ev, handler) :?> 'T

I think sprite.on returns a self reference so you shouldn't need to return sprite explicitly

[whitetigle]

Thanks! 👍 I'll try that.