Question

Could you tell me how to translate this into TypeScript?
using SharpKit.JavaScript;

namespace MyNamespace
{
    [JsType(JsMode.Prototype)]
    public class JsEventArgs
    {
    }

    public delegate void JsEventHandler<in T>(object sender, T args) where T : JsEventArgs;
    public delegate void JsEventHandler(object sender, JsEventArgs args);
}

And usage in the other class:

public event JsEventHandler<LayerVisivilityEventArgs> Changed;

I tried that:

module JsEvent {

    export class JsEventArgs {
    }

    public JsEventHandler: (sender: Object, args: any) => void;
    public JsEventHandler: (sender: Object, args: JsEventArgs) => void;
}

Answer 1

I think you need to stop thinking in C#, and begin thinking in TypeScript.

This code:

module JsEvent {

    export class JsEventArgs {
    }

    public JsEventHandler: (sender: Object, args: any) => void;
    public JsEventHandler: (sender: Object, args: JsEventArgs) => void;
}

… tries to add two properties to a module, but properties are only permitted on a class (or interface).

TypeScript doesn’t really use delegates – you can wire up an event (for example, in JQuery), like this:

$('selector').click((e:JQueryEventObject) => {
     // Do something here.
});

… or, avoiding JQuery:

var div: HTMLDivElement = new HTMLDivElement();
div.onclick = (e: MouseEvent) => {
    // Do something here.
};

… or, without an anonymous function:

div.onclick = doSomething;
function doSomething(e:MouseEvent):void{
    // Do something here.
}

I think the closest pattern you’ll get to a delegate is something like this (cribbed from http://forum.unity3d.com/threads/9679-Javascript-Delegates!):

module JSEvents {
    class JSEventClass {

        public delegate:(e:string) => any;

        constructor() => {
            this.delegate = this.doSomething;
            this.delegate("Hello, Delegate World");
        }

        public doSomething(e: string): any {
            console.log("Doing Something: " + e);
        }
    }
}

… but in a TypeScript / JavaScript world, I don’t see what this pattern achieves over just calling doSomething() directly.