About

This is a project aimed at making it easier for F# developers to write Blazor applications.

Features include:

1. Allows F# for Blazor development
2. Use computation expression (CE) style DSL for internal and third-party Blazor libraries
3. Use dependency injection with function style html.inject
4. Leverages the Adaptive model (adaptiview/AdaptiveForm) (highly recommended), or the elmish model (html.elmish)
5. Implements Giraffe-style routing (html.route)
6. Provides type-safe stylesheet creation using Fun.Css
7. Converts HTML to CE style with Fun.Dev.Tools
8. All the official blazor stuff works the same way

Simple demo

Basic counter in class style:

Basic counter that uses an adaptive model:

Basic counter that uses html.inject:

How does this work?

Fun.Blazor provides a series of delegates for Blazor to handle. For example, when you write:

let demo =
    div {
        class' "cool"
    }

This code essentially becomes:

let demo =
    NodeRenderFragment(fun comp builder index ->  // delegate
        builder.OpenElement(index, "div")
        bulder.AddAttribute(index + 1, "class", "cool")
        builer.CloseElement()
        index + 2
    )

type NodeRenderFragment = delegate of root: IComponent * builder: RenderTreeBuilder * sequence: int -> int

In essence, you have created a delegate that will be passed to a component, which will manage the rendering or building of the DOM tree. This approach is similar to what the Razor engine would generate in the C# world.

Components can be created using adaptiview, html.inject, etc. These components are normal Blazor components that inherit from ComponentBase.

Considerations before using Fun.Blazor:

There are a few things to keep in mind:

1. No support for hot-reload

2. Attribute, items position in CE

   When using a ref or renderMode attribute etc., you should place it like below, because blazor treat them very special and can only add them after other attributes:

   div {
       attributes ...
       ref (fun x -> ()) // ✅
       childContent [| ... |]
   }
   

   Or:

   div {
       attributes ...
       ref (fun x -> ()) // ✅
       div { }
   }
   

Benchmarks

BenchmarkDotNet v0.14.0, Windows 11 (10.0.22631.4317/23H2/2023Update/SunValley3) 12th Gen Intel Core i7-12700H, 1 CPU, 20 logical and 14 physical cores .NET SDK 9.0.100 [Host] : .NET 9.0.0 (9.0.24.52809), X64 RyuJIT AVX2 DEBUG DefaultJob : .NET 9.0.0 (9.0.24.52809), X64 RyuJIT AVX2