Add worker_threads module

app/current/src/main/scala/io/scalajs/nodejs/worker_threads/MessageChannel.scala

@@ -0,0 +1,14 @@
+package io.scalajs.nodejs.worker_threads
+
+import com.thoughtworks.enableMembersIf
+
+import scala.scalajs.js
+import scala.scalajs.js.annotation.JSImport
+
+@enableMembersIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+@js.native
+@JSImport("worker_threads", "MessageChannel")
+class MessageChannel extends js.Object {
+  def port1: MessagePort = js.native
+  def port2: MessagePort = js.native
+}

app/current/src/main/scala/io/scalajs/nodejs/worker_threads/MessagePort.scala

@@ -0,0 +1,17 @@
+package io.scalajs.nodejs.worker_threads
+
+import com.thoughtworks.enableMembersIf
+import io.scalajs.nodejs.events.IEventEmitter
+
+import scala.scalajs.js
+import scala.scalajs.js.annotation.JSImport
+
+@enableMembersIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+@js.native
+@JSImport("worker_threads", "MessageChannel")
+class MessagePort extends IEventEmitter with MessagePoster {
+
+  def ref(): Unit   = js.native
+  def start(): Unit = js.native
+  def unref(): Unit = js.native
+}

app/current/src/main/scala/io/scalajs/nodejs/worker_threads/MessagePoster.scala

@@ -0,0 +1,15 @@
+package io.scalajs.nodejs.worker_threads
+
+import com.thoughtworks.enableMembersIf
+
+import scala.scalajs.js
+
+@enableMembersIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+@js.native
+trait MessagePoster extends js.Object {
+
+  def postMessage(value: js.Any): Unit = js.native
+
+  def postMessage(value: js.Any, transferList: js.Array[js.|[js.typedarray.ArrayBuffer, MessagePort]]): Unit = js.native
+
+}

app/current/src/main/scala/io/scalajs/nodejs/worker_threads/Worker.scala

@@ -0,0 +1,23 @@
+package io.scalajs.nodejs.worker_threads
+
+import com.thoughtworks.enableMembersIf
+
+import scala.scalajs.js
+import scala.scalajs.js.annotation.JSImport
+
+@enableMembersIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+@js.native
+@JSImport("worker_threads", "Worker")
+class Worker(filename: String, workerOptions: WorkerOptions = js.native) extends js.Object with MessagePoster {
+  def ref(): Unit   = js.native
+  def unref(): Unit = js.native
+
+  // TODO: No need to UnderOr when Node.js v10 dropepd
+  def terminate(): js.UndefOr[js.Promise[Unit]] = js.native
+
+  def threadId: Int = js.native
+
+  def stderr: io.scalajs.nodejs.stream.Readable            = js.native
+  def stdout: io.scalajs.nodejs.stream.Readable            = js.native
+  def stdin: js.|[io.scalajs.nodejs.stream.Writable, Null] = js.native
+}

app/current/src/main/scala/io/scalajs/nodejs/worker_threads/WorkerOptions.scala

@@ -0,0 +1,15 @@
+package io.scalajs.nodejs.worker_threads
+
+import io.scalajs.nodejs.process
+
+import scala.scalajs.js
+
+class WorkerOptions(
+    var env: js.UndefOr[process.Environment] = js.undefined,
+    var eval: js.UndefOr[Boolean] = js.undefined,
+    var execArgv: js.UndefOr[js.Array[String]] = js.undefined,
+    var stdin: js.UndefOr[Boolean] = js.undefined,
+    var stdout: js.UndefOr[Boolean] = js.undefined,
+    var stderr: js.UndefOr[Boolean] = js.undefined,
+    var workerData: js.UndefOr[js.Any] = js.undefined
+) extends js.Object

app/current/src/main/scala/io/scalajs/nodejs/worker_threads/WorkerThreads.scala

@@ -0,0 +1,35 @@
+package io.scalajs.nodejs.worker_threads
+
+import com.thoughtworks.enableIf
+
+import scala.scalajs.js
+import scala.scalajs.js.annotation.JSImport
+
+@js.native
+trait WorkerThreads extends js.Object {
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+  def isMainThread: Boolean = js.native
+
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+  def parentPort: js.|[MessagePort, Null] = js.native
+
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+  def SHARE_ENV: js.Symbol = js.native
+
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+  def threadId: Int = js.native
+
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs10)
+  def workerData: js.Any = js.native
+
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs12)
+  def moveMessagePortToContext(port: MessagePort,
+                               contextifiedSandbox: io.scalajs.nodejs.vm.ScriptContext): MessagePort = js.native
+
+  @enableIf(io.scalajs.nodejs.CompilerSwitches.gteNodeJs12)
+  def receiveMessageOnPort(port: MessagePort): js.UndefOr[js.Object] = js.native
+}
+
+@js.native
+@JSImport("worker_threads", JSImport.Namespace)
+object WorkerThreads extends WorkerThreads