Kotline React GH-pages app Stage 3

So the goal of step 3 is to bring in Material UI and use a simple component. Going for a Button doing something. The simple part is to include the package.

yarn add @material-ui/core 

But to use js libraries in kotlin is a bit complicated. For each component we need to define it in Button.kt:

@file:JsModule("@material-ui/core")
@file:JsNonModule

package materialUi

import org.w3c.dom.events.Event
import react.RProps
import react.RClass

 // way 1
@JsName("Button") // because it was exported as default
external val Button : RClass;

 external interface ButtonProps: RProps {
    var className : String
    var onClick: (Event?)->Unit
    var color: String
    var href: String
}

If you have any tips to make it easier this wrapping things feels a bit complicated:

#kotlin #react whats the thing with #wrappers mingodth is it really needed. I guess it gives purpose to wrapper builders.

— Patrik Gustafsson (@paven) November 1, 2019

Now on can us Material UI Button in App.kt but frist we need a state for the button to manipulate:

    interface APPstate : RState {
        var ticker: Int;
    }
    fun APPstate.init(props: TickerProps) {
        ticker = 0
    }

Now for the button, and asmale change using the state in ticker.

override fun RBuilder.render() {
        div("App-header") {
            h2 {
                +"The awesome Page"
            }
        }
        p("App-ticker") {

            Button {  +"Timetravel"
                attrs {
                    onClick = {
                        setState { ticker += 1 }
                    }
                    variant="contained"
                }}

            br{}
            ticker(state.ticker)

        }
    }

Stage 3: Now with imported #materialUI component!https://t.co/1jX2I3UaDP#1ede71e741050afcc7df3ac765a0416aa960fe31#kotlin #React #ghpages #project

Most helpful link: https://t.co/U9X5uEe7xJ

— Patrik Gustafsson (@paven) November 1, 2019

Small changes from the original tweet: #dcb19ca8e1d7d84bf6cfc0c102a10a67405a811d