README.ktbridge.md

KtBridge

This library makes it easy call between Kotlin/JVM and Kotlin/JavaScript. It expands beyond the built-in QuickJs binding to support custom types.

Configure Kotlin/JS IR

KtBridge uses a Kotlin compiler plugin to generate code for calling between the host application and QuickJS. This requires configuring the build to use the new IR (Intermediate Representation) compiler. In your root project's gradle.properties, add this:

kotlin.js.compiler=ir

Define a Shared API

In your commonMain directory, create an interface and value types that'll be shared between platforms.

interface EchoService {
  fun echo(request: EchoRequest): EchoResponse
}

data class EchoRequest(
  val message: String
)

data class EchoResponse(
  val message: String
)

Define a JsAdapter

Create a shared JsAdapter to encode and decode your parameter types.

Set a Service in Kotlin/JS

In your jsMain directory, create a service object that you'd like to publish to Kotlin/JVM. Then call ktBridge.set() with that object. Note that you must explicitly specify the type parameter.

package com.example

import app.cash.zipline.ktbridge.ktBridge

val echoService: EchoService = ...

fun prepareJsBridges() {
  ktBridge.set<EchoService>("helloService", EchoJsAdapter, JsEchoService("hello"))
}

Get a Client in Kotlin/JVM

Load your Kotlin/JS module into QuickJS. The service should be ready before you attempt to access it from the JVM. Then get the service from a KtBridge instance:

val quickJs: QuickJs = ...
val ktBridge: KtBridge = createKtBridge(quickJs, "testing")
val helloService: EchoService = ktBridge.get("helloService", EchoJsAdapter)

Now you can call Kotlin/JS from Kotlin/JVM. Outbound parameters are encoded in the JVM and decoded in JavaScript.