traceur compatibility fixes

Author: guybedford

lib/index.js

@@ -1,4 +1,5 @@
-require('traceur');
+if (!global.traceur)
+  require('traceur');
 module.exports = {
   Loader: require('./loader'),
   Module: Module,

lib/loader.js

@@ -225,6 +225,9 @@ function logloads(loads) {
             load.kind = 'declarative';
             depsList = getImports(body);
 
+            var oldSourceMaps = traceur.options.sourceMaps;
+            var oldModules = traceur.options.modules;
+
             traceur.options.sourceMaps = true;
             traceur.options.modules = 'instantiate';
 
@@ -266,10 +269,16 @@ function logloads(loads) {
               System.register = curRegister;
             if (curSystem)
               __global.System = curSystem;
+            if (oldSourceMaps)
+              traceur.options.sourceMaps = oldSourceMaps;
+            if (oldModules)
+              traceur.options.modules = oldModules;
             throw e;
           }
           System.register = curRegister;
           __global.System = curSystem;
+          traceur.options.sourceMaps = oldSourceMaps;
+          traceur.options.modules = oldModules;
         }
         else if (typeof instantiateResult == 'object') {
           depsList = instantiateResult.deps || [];

lib/system.js

@@ -219,7 +219,8 @@
   if (global.System && global.traceur)
     global.traceurSystem = global.System;
 
-  global.System = System;
+  if (isBrowser)
+    global.System = System;
 
   // <script type="module"> support
   // allow a data-init function callback once loaded