gistfile1.txt

let actor = null
function write(something) {
    if (actor == null) {
        actor = new TextRenderActor(GWorld, { X: 800, Z: 100 }, { Yaw: 180 })
        actor.TextRender.SetHorizontalAlignment('EHTA_Center')
    }
    
    actor.TextRender.K2_SetText(something)
}

function load(url) {
    write("loading " + url)
    return new Promise((resolve, reject) => {
        var req = new JavascriptHttpRequest()
        req.SetVerb("GET")
        req.SetURL(url)
        req.OnComplete.Add(function (success) {
            if (success) {
                let result = eval(req.GetContentAsString())
                write("loading " + url + ":done")
                try {
                    resolve(result)
                    write("done!!!")
                } catch (e) {
                    write(String(e))   
                }
            } else {
                write("loading " + url + ":fail")
                reject()
            }
        })
        req.ProcessRequest()
    })
}


load("https://gist.githubusercontent.com/nakosung/d8a00066ee52af1959da/raw").then(function () {
    write("invoking main")
    // set cursor type
    GetPC().DefaultMouseCursor = Symbol('Default')

    let str = []
                
    // declare our own HUD class
    class MyHUD extends HUD {
        ctor() {
            this.count = 0
        }
            
        // override ReceiveDrawHUD
        ReceiveDrawHUD() {
            // don't forget to its super function
            super.ReceiveDrawHUD()
                
            // have fun with Canvas
            let text = str.join("\n")

            if (this.count-- < 0) {
                this.count = 100
                str.pop()
            }

            this.Canvas.K2_DrawText(
                GEngine.LargeFont,
                text,
                { X: this.Canvas.SizeX / 2, Y: this.Canvas.SizeY / 2 },
                { R: 1, G: 1, B: 1, A: 1 },
                0,
                { R: 0, G: 0, B: 0, A: 1 },
                { X: 1, Y: 1 },
                true, true, true,
                { R: 0, G: 0, B: 0, A: 1 }
                )
        }
    }
        
    // register new HUD class
    let MyHUD_C = require('uclass')()(global, MyHUD);            

    // and instantiate it
    GetPC().ClientSetHUD(MyHUD_C)
    
    function testUI() {
        let cleanup = null

        let PC = GetPC()
        let widget = null
        // create a widget   
    
        widget = GWorld.CreateWidget(JavascriptWidget, PC)
        widget.JavascriptContext = Context
        widget.bSupportsKeyboardFocus = true

        let UMG = require('UMG')
    
        // low-level json which describes UMG structure to set up.
        let design = UMG.span({},
            UMG(Button, { id: 'button' }, UMG.text({}, "RELOAD!"))
            )

        let instantiator = require('instantiator')
        let page = instantiator(design)

        let bye = null
        page.find('button').OnClicked.Add(() => {
            //cleanup()
            write("loading client!")
            if (bye) {
                bye()
            }            
            load(THE_URL+"?random=" + Math.random()).then((result) => {
                write("client loaded!")
                bye = result
            })
            //load("https://gist.githubusercontent.com/nakosung/756aed5399da66ed40d7/raw?random=" + Math.random())
        })

        page.Visibility = 'Visible'

        widget.SetRootWidget(page)
        widget.AddToViewport()    
    
        // Switch PC to UI only mode.
        PC.bShowMouseCursor = true
        PC.SetInputMode_UIOnly(page)

        cleanup = () => {
            widget.RemoveFromViewport()
            if (bye) {
                bye()
            }            
        }
    }

    try {
        testUI()
    } catch (e) {
        str += String(e)
        str += String(e.stack)
    }
}).catch((error) => {
    write(error)
})