Do not concat hidden files (such as .DS_Store)

https://stackoverflow.com/questions/8905680/nodejs-check-for-hidden-files/20285137#20285137

Author: mudcube

bin/concat.js

@@ -10,6 +10,7 @@ fs.writeFileSync(path.resolve(process.cwd(), bundlePath), '');
 // loop folders
 folders.forEach(folder => {
   fs.readdir(folder, (err, files) => {
+    files = files.filter(file => !(/(^|\/)\.[^\/\.]/g).test(file))
     files.forEach(file => {
       // console.log(file);
       let filePath = path.resolve(process.cwd(), `${folder}${file}`);
@@ -23,5 +24,4 @@ folders.forEach(folder => {
       });
     });
   });
-
 });