Add an option for ES6 exporting (fixes #6284) (#6483)

emcc.py

@@ -2503,26 +2503,35 @@ def modularize():
   src = open(final).read()
   final = final + '.modular.js'
   f = open(final, 'w')
+
   # Included code may refer to Module (e.g. from file packager), so alias it
-  # Export the function as Node module, otherwise it is lost when loaded in Node.js or similar environments
   f.write('''var %(EXPORT_NAME)s = function(%(EXPORT_NAME)s) {
   %(EXPORT_NAME)s = %(EXPORT_NAME)s || {};
 
 %(src)s
 
   return %(EXPORT_NAME)s;
 }%(instantiate)s;
-if (typeof exports === 'object' && typeof module === 'object')
-  module.exports = %(EXPORT_NAME)s;
-else if (typeof define === 'function' && define['amd'])
-  define([], function() { return %(EXPORT_NAME)s; });
-else if (typeof exports === 'object')
-  exports["%(EXPORT_NAME)s"] = %(EXPORT_NAME)s;
 ''' % {
   'EXPORT_NAME': shared.Settings.EXPORT_NAME,
   'src': src,
   'instantiate': '()' if shared.Settings.MODULARIZE_INSTANCE else ''
 })
+
+  # Export using a UMD style export, or ES6 exports if selected
+  if shared.Settings.EXPORT_ES6:
+    f.write('''export default %s;''' % shared.Settings.EXPORT_NAME)
+  else:
+    f.write('''if (typeof exports === 'object' && typeof module === 'object')
+    module.exports = %(EXPORT_NAME)s;
+  else if (typeof define === 'function' && define['amd'])
+    define([], function() { return %(EXPORT_NAME)s; });
+  else if (typeof exports === 'object')
+    exports["%(EXPORT_NAME)s"] = %(EXPORT_NAME)s;
+  ''' % {
+    'EXPORT_NAME': shared.Settings.EXPORT_NAME
+  })
+
   f.close()
   if DEBUG: save_intermediate('modularized', 'js')
 

src/settings.js

@@ -628,6 +628,8 @@ var MODULARIZE_INSTANCE = 0; // Similar to MODULARIZE, but while that mode expor
                              // Note that the promise-like API MODULARIZE provides isn't
                              // available here (since you arean't creating the instance
                              // yourself).
+var EXPORT_ES6 = 0; // Export using an ES6 Module export rather than a UMD export.
+                    // MODULARIZE must be enabled for ES6 exports.
 
 var BENCHMARK = 0; // If 1, will just time how long main() takes to execute, and not
                    // print out anything at all whatsoever. This is useful for benchmarking.