JavaScriptEngine is thread-safe and meant to be an app-wide singleton.

Author: Daniel15

build.proj

@@ -11,7 +11,7 @@ of patent rights can be found in the PATENTS file in the same directory.
 	<PropertyGroup>
 		<Major>1</Major>
 		<Minor>0</Minor>
-		<Build>0</Build>
+		<Build>1</Build>
 		<Revision>0</Revision>
 		<DevBuild>true</DevBuild>
 		<DevNuGetServer>http://reactjs.net/packages/</DevNuGetServer>

src/React/AssemblyRegistration.cs

@@ -37,9 +37,9 @@ public void Register(TinyIoCContainer container)
 			// One instance shared for the whole app
 			container.Register<IReactSiteConfiguration>((c, o) => ReactSiteConfiguration.Configuration);
 			container.Register<IFileCacheHash, FileCacheHash>().AsSingleton();
+			container.Register<IJavaScriptEngineFactory, JavaScriptEngineFactory>().AsSingleton();
 
 			container.Register<IReactEnvironment, ReactEnvironment>().AsPerRequestSingleton();
-			container.Register<IJavaScriptEngineFactory, JavaScriptEngineFactory>().AsPerRequestSingleton();
 
 			// JavaScript engines
 			container.Register(new JavaScriptEngineFactory.Registration

src/React/ReactEnvironment.cs

@@ -21,7 +21,7 @@ namespace React
 	/// Request-specific ReactJS.NET environment. This is unique to the individual request and is 
 	/// not shared.
 	/// </summary>
-	public class ReactEnvironment : IReactEnvironment
+	public class ReactEnvironment : IReactEnvironment, IDisposable
 	{
 		/// <summary>
 		/// Format string used for React component container IDs
@@ -328,5 +328,13 @@ private static string GetVersion()
 			var build = rawVersion.Substring(lastDot + 1);
 			return string.Format("{0} (build {1})", version, build);
 		}
+
+		/// <summary>
+		/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+		/// </summary>
+		public void Dispose()
+		{
+			_engineFactory.DisposeEngineForCurrentThread();
+		}
 	}
 }