Grunt file with compressed and customized

Gruntfile.js

module.exports = function(grunt) {

    // Load automatically all tasks without using grunt.loadNpmTasks()
    // for each module
    require('load-grunt-tasks')(grunt);

    /* ---------------------------------------
    * Tasks configuration
    * --------------------------------------- */
    grunt.initConfig({

        /*
        * Paths
        */
        paths: {
            resources: 'scss', // source files (scss)
            assets: ''       // compiled files (css)
        },

        /* 
        * SASS task
        */
        sass: {

            // For development
            dev: {
                files: {
                    'style.css' : '<%= paths.resources %>/style.scss'
                },
                options: {
                    style: 'compressed' //nested, compact, compressed, expanded
                }
            },

        // For production
        prod: {
          files: {
            '<%= paths.assets %>/css/main.css' : '<%= paths.resources %>/sass/main.scss'
          },
          options: {
            style: 'compressed', // //nested, compact, compressed, expanded
            sourcemap: 'none'
          }
        }

        },

        /* 
        * Watch task
        */
        watch: {
            sass: {
                files: [
                    '<%= paths.resources %>/**/*.scss' // Write here the files that Grunt must watches
                ],
                tasks: ['sass:dev']
            },
            uglify: {
                files:[
                    'js/app.js'
                ],
                tasks: ['uglify:minfiles']
            }
        },
        uglify: {
            minfiles: {
                options: {
                    sourceMap: {
                        includeSources: true
                    },
                },
                files: {
                    'dest/app.min.js': 'js/app.js',
                },
            }
        }

    });


    /* ---------------------------------------
    * Registered tasks
    * --------------------------------------- */
    grunt.registerTask('default', ['sass:dev']);
    grunt.registerTask('jsmin', ['uglify:minfiles']);
    grunt.registerTask('prod', ['sass:prod']);

};