Update to Kotlin 1.9.22 and migrate to Kotlin/Wasm

README.md

@@ -1,27 +1,31 @@
 # Kotlin hello world for Cloudflare Workers
 
-Your Kotlin code in [main.kt](https://github.com/cloudflare/kotlin-worker-hello-world/blob/master/src/main/kotlin/main.kt), running on Cloudflare Workers
+Your Kotlin code in [main.kt](src/wasmJsMain/kotlin/main.kt), running on Cloudflare Workers
 
-In addition to [Wrangler v2.x](https://github.com/cloudflare/wrangler2) you will need to install Kotlin, including a JDK and support for Gradle projects. The easiest way to do this is using the free Community Edition of [IntelliJ IDEA](https://kotlinlang.org/docs/tutorials/jvm-get-started.html).
+In addition to [Wrangler v2.x](https://github.com/cloudflare/wrangler2) you will need to install a JDK 8 or newer. [The easiest way to do this](https://www.jetbrains.com/guide/java/tips/download-jdk/) is using the free Community Edition of [IntelliJ IDEA](https://www.jetbrains.com/idea/download/).
 
 ## Wrangler
 
 Configure the [wrangler.toml](wrangler.toml) by filling in the `account_id` from the Workers pages of your Cloudflare Dashboard.
 
 Further documentation for Wrangler can be found [here](https://developers.cloudflare.com/workers/tooling/wrangler).
 
-## Gradle
+## Build & Deploy
 
-After setting up Kotlin per the linked instructions above,
+After setting up your environment, run the following command:
 
-```
-./gradlew :compileProductionExecutableKotlinJs
+```shell
+./gradlew :compileProductionExecutableKotlinWasmJs
 ```
 
-That will compile your code and package it into a JavaScript executable, after which you can run `wrangler publish` to push it to Cloudflare.
+That will compile your code into a WebAssembly executable and JavaScript glue code, 
+after which you can run `wrangler deploy` to push it to Cloudflare:
 
+```shell
+npx wrangler@latest deploy build/js/packages/kotlin-worker-hello-world-wasm-js/kotlin/kotlin-worker-hello-world.js
 ```
-wrangler publish build/js/packages/kotlin-worker-hello-world/kotlin/kotlin-worker-hello-world.js
-```
 
-For more information on interop between Kotlin and Javascript, see the [Kotlin docs](https://kotlinlang.org/docs/reference/js-interop.html).  Regarding coroutines, see [this issue and workaround](https://github.com/cloudflare/kotlin-worker-hello-world/issues/2)
+## Learn more
+
+* [Kotlin/Wasm Overview](https://kotl.in/wasm/)
+* [Kotlin/Wasm JavaScript interop](https://kotlinlang.org/docs/wasm-js-interop.html).

build.gradle.kts

@@ -1,5 +1,10 @@
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension
+import org.jetbrains.kotlin.gradle.targets.js.npm.tasks.KotlinNpmInstallTask
+import org.jetbrains.kotlin.gradle.targets.js.ir.*
+
 plugins {
-    kotlin("js") version "1.7.10"
+    kotlin("multiplatform") version "1.9.22"
+    // kotlin("multiplatform") version "2.0.0-RC1"
 }
 
 group = "org.example"
@@ -10,9 +15,62 @@ repositories {
 }
 
 kotlin {
-    js(IR) {
+    wasmJs {
         nodejs {
         }
         binaries.executable()
+
+        // Comment the next line to turn off optimization by Binaryen
+        applyBinaryen()
+
+        // Workaround for https://youtrack.jetbrains.com/issue/KT-66972
+        compilations
+            .configureEach {
+                binaries.withType<Executable>().configureEach {
+                        linkTask.configure {
+                            val moduleName = linkTask.flatMap {
+                                it.compilerOptions.moduleName
+                            }
+                            val fileName = moduleName.map { module ->
+                                "$module.uninstantiated.mjs"
+                            }
+
+                            val mjsFile: Provider<RegularFile> = linkTask.flatMap {
+                                it.destinationDirectory.file(fileName.get())
+                            }
+
+                            doLast {
+                                val module = moduleName.get()
+                                val file = mjsFile.get().asFile
+                                val text = file.readText()
+                                val newText = text
+                                    .replace("if \\(!\\w+( && !\\w+)*\\) \\{[^\\}]*\\}".toRegex(), "")
+                                    .replace(
+                                        "(if \\(isBrowser\\) \\{\\s*wasmInstance[^\\}]*\\})".toRegex(),
+                                        """
+                                        $1
+
+                                              const isWorker = navigator.userAgent.includes("Workers")
+                                              if (isWorker) {
+                                                  const { default: wasmModule } = await import('./$module.wasm');
+                                                  wasmInstance = (await WebAssembly.instantiate(wasmModule, importObject));
+                                              }
+                                        """.trimIndent()
+                                    )
+
+                                file.writeText(newText)
+                            }
+                        }
+                    }
+            }
     }
 }
+
+// To run in Node.js
+rootProject.the<NodeJsRootExtension>().apply {
+    nodeVersion = "22.0.0-nightly2024021536dcd399c0"
+    nodeDownloadBaseUrl = "https://nodejs.org/download/nightly"
+}
+tasks.withType<KotlinNpmInstallTask>().configureEach {
+    args.add("--ignore-engines")
+}

src/main/kotlin/main.kt → src/wasmJsMain/kotlin/main.kt

@@ -1,14 +1,15 @@
+import org.w3c.fetch.Headers
 import org.w3c.fetch.Request
 import org.w3c.fetch.Response
 import org.w3c.fetch.ResponseInit
 
 @OptIn(ExperimentalJsExport::class)
 @JsExport
 fun fetch(request: Request) : Response {
-    val headers: dynamic = object {}
-    headers["content-type"] = "text/plain"
+    val headers = Headers()
+    headers.append("content-type", "text/plain")
     return Response(
-        "Kotlin Worker hello world",
+        "Hello from Kotlin/Wasm Worker".toJsString(),
         ResponseInit(headers = headers)
     )
 }

src/wasmJsMain/resources/kotlin-worker-hello-world.js

@@ -0,0 +1,5 @@
+import * as foo from "./kotlin-worker-hello-world-wasm-js.mjs"
+
+let keys = Object.keys(foo);
+
+export default keys.length === 1 && keys[0] === "default" ? { ... foo.default } : foo;