A base Gruntfile and package.json setup that minifies js files, compiles sass files and sets up watch on a base folder (app/)

Gruntfile.js

module.exports = function(grunt) {
  grunt.initConfig({
    // concatenates all your js files
    concat: {
      js: {
        src: ['app/app.js', 'app/js/**/**.js'],
        dest: 'tmp/app.js'
      }
    },
    // minifies your js files
    uglify: {
      options: {
        mangle: false,
        uglify: true
      },
      default: {
        files: {
          "app.min.js": ["tmp/app.js"]
        }
      }
    },
    // compile sass files to css
    sass: {
      dist: {
        options: {
          style: 'expanded'
        },
        files: {
          'css/style.css': 'app/sass/app.scss'
        }
      }
    },
    // watches for changes in project, reloads browser
    watch: {
      options: {
        livereload: true
      },
      files: ['app/**/*', 'app/**/**/*', 'index.html'],
      tasks: ['concat:js', 'sass', 'uglify'],
    }
  });

  grunt.loadNpmTasks('grunt-contrib-concat');
  grunt.loadNpmTasks('grunt-contrib-uglify');
  grunt.loadNpmTasks('grunt-contrib-sass');
  grunt.loadNpmTasks('grunt-contrib-watch');

  // The default tasks to run when you type 'grunt'
  grunt.registerTask('default', ['watch']);
};

package.json

{
  "name": "Base App",
  "title": "baseApp",
  "version": "1.0.0",
  "devDependencies": {
    "grunt": "0.4.2",
    "grunt-contrib-concat": "0.3.0",
    "grunt-contrib-watch" : "0.5.3",
    "grunt-contrib-uglify" : "0.2.2",
    "grunt-contrib-sass": "0.7.2"
  }
}