Add wasmJs support

build.gradle.kts

@@ -4,6 +4,10 @@ import io.gitlab.arturbosch.detekt.DetektPlugin
 import io.gitlab.arturbosch.detekt.extensions.DetektExtension
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 import org.gradle.api.tasks.testing.logging.TestLogEvent
+import org.gradle.nativeplatform.platform.internal.DefaultNativePlatform
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootPlugin
+import org.jetbrains.kotlin.gradle.targets.js.npm.tasks.KotlinNpmInstallTask
 
 @Suppress("DSL_SCOPE_VIOLATION")
 plugins {
@@ -107,3 +111,32 @@ allprojects {
     parent?.subprojects?.forEach { dependsOn(it.tasks.withType(taskClass)) }
   }
 }
+
+/**
+ * [Reference](https://github.com/square/okio/blob/55b7210fb3d52de07f4bc1122c5062e38df576d9/build.gradle.kts#L227-L248).
+ *
+ * Select a NodeJS version with WASI and WASM GC.
+ * https://github.com/Kotlin/kotlin-wasm-examples/blob/main/wasi-example/build.gradle.kts
+ */
+plugins.withType<NodeJsRootPlugin> {
+  extensions.getByType<NodeJsRootExtension>().apply {
+    if (DefaultNativePlatform.getCurrentOperatingSystem().isWindows) {
+      // We're waiting for a Windows build of NodeJS that can do WASM GC + WASI.
+      nodeVersion = "21.4.0"
+    } else {
+      // Reference:
+      // https://github.com/drewhamilton/Poko/blob/72ec8d24cf48a74b3d1125c94f0e625ab956b93f/build.gradle.kts#L17-L19
+      // WASM requires a canary Node.js version. This is the last v21 canary, and has both
+      // darwin-arm64 and darwin-x64 artifacts:
+      nodeVersion = "21.0.0-v8-canary20231024d0ddc81258"
+      nodeDownloadBaseUrl = "https://nodejs.org/download/v8-canary"
+    }
+  }
+  // Suppress an error because yarn doesn't like our Node version string.
+  //   warning You are using Node "21.0.0-v8-canary20231024d0ddc81258" which is not supported and
+  //   may encounter bugs or unexpected behavior.
+  //   error [email protected]: The engine "node" is incompatible with this module.
+  tasks.withType<KotlinNpmInstallTask>().all {
+    args += "--ignore-engines"
+  }
+}

channel-event-bus/build.gradle.kts

@@ -27,16 +27,26 @@ kotlin {
       }
     }
   }
+
   js(IR) {
-    compilations.all {
-      kotlinOptions {
-        sourceMap = true
-        moduleKind = "commonjs"
+    moduleName = property("POM_ARTIFACT_ID")!!.toString()
+    compilations.configureEach {
+      compilerOptions.configure {
+        sourceMap.set(true)
+        moduleKind.set(org.jetbrains.kotlin.gradle.dsl.JsModuleKind.MODULE_COMMONJS)
       }
     }
     browser()
     nodejs()
   }
+  @OptIn(org.jetbrains.kotlin.gradle.targets.js.dsl.ExperimentalWasmDsl::class)
+  wasmJs {
+    // Module name should be different from the one from JS
+    // otherwise IC tasks that start clashing different modules with the same module name
+    moduleName = property("POM_ARTIFACT_ID")!!.toString() + "Wasm"
+    browser()
+    nodejs()
+  }
 
   // According to https://kotlinlang.org/docs/native-target-support.html
   // Tier 1: macosX64, macosArm64, iosSimulatorArm64, iosX64
@@ -95,6 +105,12 @@ kotlin {
       }
     }
 
+    val wasmJsTest by getting {
+      dependencies {
+        implementation(kotlin("test-wasm-js"))
+      }
+    }
+
     jvmTest {
       dependencies {
         implementation(kotlin("test-junit"))