So siehts ganz gut aus !

node_modules/mime/build/build.js

@@ -0,0 +1,11 @@
+var db = require('mime-db');
+
+var mapByType = {};
+Object.keys(db).forEach(function(key) {
+  var extensions = db[key].extensions;
+  if (extensions) {
+    mapByType[key] = extensions;
+  }
+});
+
+console.log(JSON.stringify(mapByType));