Add ability to configure environment variables for Node instances, plus auto-populate NODE_ENV based on IHostingEnvironment when possible. Fixes #230

src/Microsoft.AspNetCore.NodeServices/Configuration/NodeServicesOptions.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using Microsoft.AspNetCore.NodeServices.HostingModels;
 using Microsoft.Extensions.Logging;
 
@@ -22,6 +23,23 @@ namespace Microsoft.AspNetCore.NodeServices
         public string[] WatchFileExtensions { get; set; }
         public ILogger NodeInstanceOutputLogger { get; set; }
         public bool LaunchWithDebugging { get; set; }
+        public IDictionary<string, string> EnvironmentVariables { get; set; }
         public int? DebuggingPort { get; set; }
+
+        public NodeServicesOptions AddDefaultEnvironmentVariables(bool isDevelopmentMode)
+        {
+            if (EnvironmentVariables == null)
+            {
+                EnvironmentVariables = new Dictionary<string, string>();
+            }
+
+            if (!EnvironmentVariables.ContainsKey("NODE_ENV"))
+            {
+                // These strings are a de-facto standard in Node
+                EnvironmentVariables["NODE_ENV"] = isDevelopmentMode ? "development" : "production";
+            }
+
+            return this;
+        }
     }
 }