Add OMIT_MODULE_EXPORTS to omit module code

AUTHORS

@@ -526,3 +526,4 @@ a license to everyone to use it as detailed in LICENSE.)
 * Wouter van Oortmerssen <wvo@google.com> (copyright owned by Google, LLC)
 * Alexey Sokolov <sokolov@google.com> (copyright owned by Google, LLC)
 * Ivan Romanovski <ivan.romanovski@gmail.com>
+* Kevin Lubick <kjlubick@google.com> (copyright owned by Google, LLC)

emcc.py

@@ -2874,19 +2874,19 @@ def modularize():
   with open(final_js, 'w') as f:
     f.write(src)
 
-    # 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)
-    elif not shared.Settings.MINIMAL_RUNTIME:
-      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})
+    if not shard.Settings.OMIT_MODULE_EXPORTS:
+      # 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)
+      elif not shared.Settings.MINIMAL_RUNTIME:
+        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})
 
   save_intermediate('modularized')
 

src/settings.js

@@ -906,7 +906,7 @@ var STRICT = 0;
 // include `_main`.
 var IGNORE_MISSING_MAIN = 1;
 
-// Automatically attempt to add archive indexes at link time to archives that 
+// Automatically attempt to add archive indexes at link time to archives that
 // don't already have them.  This can happen when GNU ar or GNU ranlib is used
 // rather than `llvm-ar` or `emar` since the former don't understand the wasm
 // object format.
@@ -964,7 +964,7 @@ var DETERMINISTIC = 0;
 // (If WASM_ASYNC_COMPILATION is off, that is, if compilation is
 // *synchronous*, then it would not make sense to return a Promise, and instead
 // the Module object itself is returned, which is ready to be used.)
-// 
+//
 // The default name of the function is `Module`, but can be changed using the
 // `EXPORT_NAME` option. We recommend renaming it to a more typical name for a
 // factory function, e.g. `createModule`.
@@ -973,14 +973,14 @@ var DETERMINISTIC = 0;
 // You use the factory function like so:
 //
 //   const module = await EXPORT_NAME();
-//   
+//
 // or:
 //
 //   let module;
 //   EXPORT_NAME().then(instance => {
 //     module = instance;
 //   });
-//   
+//
 //
 // The factory function accepts 1 parameter, an object with default values for
 // the module instance:
@@ -1016,6 +1016,10 @@ var DETERMINISTIC = 0;
 // code, allowing better dead code elimination and minification.
 var MODULARIZE = 0;
 
+// By default, if MODULARIZE=1, emscripten will output JS to support UMD exports.
+// If OMIT_MODULE_EXPORTS=1, this code is omitted.
+var OMIT_MODULE_EXPORTS = 0;
+
 // Export using an ES6 Module export rather than a UMD export.  MODULARIZE must
 // be enabled for ES6 exports.
 var EXPORT_ES6 = 0;