Created support for Vercel using Node.js runtime

build.sbt

@@ -185,7 +185,6 @@ lazy val vercelNodeJS = project
   )
 
 lazy val examples = crossProject(JSPlatform, JVMPlatform)
-  .crossType(CrossType.Pure)
   .in(file("examples"))
   .settings(
     libraryDependencies ++= Seq(
@@ -198,6 +197,12 @@ lazy val examples = crossProject(JSPlatform, JVMPlatform)
   )
   .settings(commonSettings)
   .dependsOn(lambda, lambdaHttp4s)
+  .jsConfigure(_.dependsOn(vercelNodeJS))
+  .jsSettings(
+    scalaJSUseMainModuleInitializer := true,
+    Compile / mainClass := Some("feral.examples.vercelNodejsHandler"),
+    scalaJSLinkerConfig ~= { _.withModuleKind(ModuleKind.CommonJSModule) }
+  )
   .enablePlugins(NoPublishPlugin)
 
 lazy val unidocs = project
@@ -212,8 +217,7 @@ lazy val unidocs = project
         inProjects(
           lambda.jvm,
           lambdaHttp4s.jvm,
-          lambdaCloudFormationCustomResource.jvm,
-          vercelNodeJS
+          lambdaCloudFormationCustomResource.jvm
         )
     }
   )

examples/js/src/main/scala/feral/examples/VercelNodejs.scala

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2021 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package feral.examples
+
+import cats.effect._
+import feral.vercel._
+import org.http4s._
+import org.http4s.dsl.io._
+
+object vercelNodejsHandler extends IOVercel {
+  def handler = {
+    val app = HttpRoutes
+      .of[IO] {
+        case GET -> Root / "hello" / name =>
+          Ok(s"Hello, $name.")
+      }
+      .orNotFound
+
+    Resource.pure(app)
+
+    /*Resource.pure(HttpApp.pure(Response[IO](Status.Ok)))*/
+  }
+
+}

vercel-nodejs/src/main/scala/feral/vercel/IOVercel.scala

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2021 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package feral.vercel
+
+import cats.effect.IO
+import cats.effect.kernel.Resource
+import cats.effect.std.Dispatcher
+import cats.effect.unsafe.IORuntime
+import cats.syntax.all._
+import org.http4s.HttpApp
+import org.http4s.nodejs.IncomingMessage
+import org.http4s.nodejs.ServerResponse
+
+import scala.scalajs.js
+
+abstract class IOVercel {
+
+  final def main(args: Array[String]): Unit =
+    js.Dynamic.global.module.exports = handlerFn
+
+  protected def runtime: IORuntime = IORuntime.global
+
+  def handler: Resource[IO, HttpApp[IO]]
+
+  private[vercel] lazy val handlerFn: js.Function2[IncomingMessage, ServerResponse, Unit] = {
+    val dispatcherHandle = {
+      Dispatcher
+        .parallel[IO](await = false)
+        .product(handler)
+        .allocated
+        .map(_._1) // drop unused finalizer
+        .unsafeToPromise()(runtime)
+    }
+
+    (request: IncomingMessage, response: ServerResponse) =>
+      val _ = dispatcherHandle.`then`[Unit] {
+        case (dispatcher, handle) =>
+          dispatcher.unsafeRunAndForget(
+            request.toRequest[IO].flatMap(handle(_)).flatMap(response.writeResponse[IO])
+          )
+      }
+  }
+}