How to import react-bootstrap component with children into kotlin-js react app

Question

I want to use a bootstrap Card component in a react website created with kotlin-js. The app uses kotlin-react wrapper and react-bootstrap library.

react-bootstrap documentation says use <Card.Body> to put content.

<Card>
  <Card.Body>This is some text within a card body.</Card.Body>
</Card>

So far I managed to import the Card JavaScript module into kotlin-js.

@file:JsModule("react-bootstrap/Card")

import react.RClass
import react.RProps


@JsName("default")
external val Card: RClass<RProps>

With this I could use the Card within a RComponent.

class Content : RComponent<RProps, RState>() {
    override fun RBuilder.render() {
        Card {
           +"Hello World"
        }
    }
}

What renders to:

<div class="card">
  Hello World
</div>

What I additionally need is the CardBody component.

Something like this:

class Content : RComponent<RProps, RState>() {
    override fun RBuilder.render() {
        Card {
            CardBody {
                + "Hello World"
            }
        }
    }
}

---

But the CardBody is not a separate react-bootstrap component which could be imported like the Card component. It is a value inside the Card component.

---

The typescript definition file Card.d.ts looks like this:

import CardImg from './CardImg';
import { BsPrefixPropsWithChildren, BsPrefixRefForwardingComponent } from './helpers';
import { Color, Variant } from './types';
declare const CardBody: BsPrefixRefForwardingComponent<any, {}>;
declare const CardTitle: BsPrefixRefForwardingComponent<any, {}>;
declare const CardSubtitle: BsPrefixRefForwardingComponent<any, {}>;
declare const CardLink: BsPrefixRefForwardingComponent<any, {}>;
declare const CardText: BsPrefixRefForwardingComponent<any, {}>;
declare const CardHeader: BsPrefixRefForwardingComponent<any, {}>;
declare const CardFooter: BsPrefixRefForwardingComponent<any, {}>;
declare const CardImgOverlay: BsPrefixRefForwardingComponent<any, {}>;
export interface CardProps extends BsPrefixPropsWithChildren {
    bg?: Variant;
    text?: Color;
    border?: Variant;
    body?: boolean;
}
declare type Card = BsPrefixRefForwardingComponent<'div', CardProps> & {
    Img: typeof CardImg;
    Title: typeof CardTitle;
    Subtitle: typeof CardSubtitle;
    Body: typeof CardBody;
    Link: typeof CardLink;
    Text: typeof CardText;
    Header: typeof CardHeader;
    Footer: typeof CardFooter;
    ImgOverlay: typeof CardImgOverlay;
};
declare const Card: Card;
export default Card;

If I use dukat to convert the TypeScript definition files to Kotlin declarations. It puts out a Card.module_react-bootstrap.kt file

@file:JsModule("react-bootstrap")
@file:JsNonModule
@file:Suppress("INTERFACE_WITH_SUPERCLASS", "OVERRIDING_FINAL_MEMBER", "RETURN_TYPE_MISMATCH_ON_OVERRIDE", "CONFLICTING_OVERLOADS")

import kotlin.js.*
import kotlin.js.Json
import org.khronos.webgl.*
import org.w3c.dom.*
import org.w3c.dom.events.*
import org.w3c.dom.parsing.*
import org.w3c.dom.svg.*
import org.w3c.dom.url.*
import org.w3c.fetch.*
import org.w3c.files.*
import org.w3c.notifications.*
import org.w3c.performance.*
import org.w3c.workers.*
import org.w3c.xhr.*

external var CardBody: BsPrefixRefForwardingComponent<Any, Any>

external var CardTitle: BsPrefixRefForwardingComponent<Any, Any>

external var CardSubtitle: BsPrefixRefForwardingComponent<Any, Any>

external var CardLink: BsPrefixRefForwardingComponent<Any, Any>

external var CardText: BsPrefixRefForwardingComponent<Any, Any>

external var CardHeader: BsPrefixRefForwardingComponent<Any, Any>

external var CardFooter: BsPrefixRefForwardingComponent<Any, Any>

external var CardImgOverlay: BsPrefixRefForwardingComponent<Any, Any>

external interface CardProps : BsPrefixPropsWithChildren {
    var bg: dynamic /* String | String | String | String | String | String | String | String | String? */
        get() = definedExternally
        set(value) = definedExternally
    var text: String? /* 'primary' | 'secondary' | 'success' | 'danger' | 'warning' | 'info' | 'dark' | 'light' | 'white' | 'muted' */
        get() = definedExternally
        set(value) = definedExternally
    var border: dynamic /* String | String | String | String | String | String | String | String | String? */
        get() = definedExternally
        set(value) = definedExternally
    var body: Boolean?
        get() = definedExternally
        set(value) = definedExternally
}

external interface `T$0` {
    var Img: Any
    var Title: Any
    var Subtitle: Any
    var Body: Any
    var Link: Any
    var Text: Any
    var Header: Any
    var Footer: Any
    var ImgOverlay: Any
}

@JsName("default")
external var Card: BsPrefixRefForwardingComponent<String /* 'div' */, CardProps> /* BsPrefixRefForwardingComponent<String /* 'div' */, CardProps> & `T$0` */

But this doesn't compile.

---

1. How to write a kotlin declaration file for a component which has components children inside and not as separate component file?
2. How to use this component in the RBuilder.render() method?

Answer 1

Reading the Typescript declerations, it seems

file: Card.kt

@file:JsModule("react-bootstrap/Card")

package bootstrap

import react.RClass
import react.RProps

@JsName("default")
external val Card: RClass<RProps>

file: Card.ktx.kt (Since you can't have non external declarations in a JsModule)

package bootstrap

import react.RClass
import react.RProps

val CardBody : RClass<RProps> = Card.asDynamic().Body

val CardLink : RClass<RProps> = Card.asDynamic().Link

Usage

fun RBuilder.MyComp(){
  Card {
    CardBody {+"Card body goes here" }
  }
}

should work.

Answer 2

if you want to use css to external elements you can do this,

first you need to let your elements props to implement the WithClassName interface :

@file:JsModule("react-bootstrap")
@file:JsNonModule

import react.RProps
import react.RClass
import react.dom.WithClassName


@JsName("Card")
external val bsCard : RClass<bsCardProps>

external interface bsCardProps: WithClassName

then use styled function in another .kt file like this:

import styled.styled


val styledBsCard = styled(bsCard)

now use the styledBsCard like styled elements:

override fun RBuilder.render() {
styledBsCard {
            css {
                width = 200.px
                backgroundColor = Color.blue
                marginLeft = 100.px
            }
            //something other elements
        }
}