Output a file per folder in gulp

gulpfile.js

var fs = require('fs');
var path = require('path');
var es = require('event-stream');
var gulp = require('gulp');
var concat = require('gulp-concat');
var rename = require('gulp-rename');
var uglify = require('gulp-uglify');

var scriptsPath = './src/scripts/';

function getFolders(dir){
    return fs.readdirSync(dir)
      .filter(function(file){
        return fs.statSync(path.join(dir, file)).isDirectory();
      });
}

gulp.task('scripts', function() { 
   var folders = getFolders(scriptsPath);

   var tasks = folders.map(function(folder) {
      // concat into foldername.js
      // write to output
      // minify
      // rename to folder.min.js
      // write to output again
      return gulp.src(path.join(scriptsPath, folder, '/*.js'))
        .pipe(concat(folder + '.js'))
        .pipe(gulp.dest(scriptsPath))
        .pipe(uglify())
        .pipe(rename(folder + '.min.js'))
        .pipe(gulp.dest(scriptsPath));
   });

   return es.concat.apply(null, tasks);
});