gruntfile.js

module.exports = function(grunt) {
    grunt.initConfig({
        pkg: grunt.file.readJSON('package.json'),
        autoprefixer: {
            dist: {
                files: [{
                  expand: true,
                  cwd: 'css/',
                  src: 'build/{,*/}*.css',
                  dest: 'build/'
                }]
            }
        },
        uglify: {
            compressjs: {
                options: {
                    mangle: true,
                    compress: true,
                    beautify: false,
                    sourcemap: false,
                    preserveComments: false,
                    compress:{
                        drop_console: true
                    }
                },
                files: {
                    'js/build/output.min.js': ['js/src/*.js']
                }
            }
        },
        cssmin: {
            minify: {
                files: {
                    'css/build/output.min.css': ['css/src/*.css']
                }
            }
        }
    });
    grunt.loadNpmTasks('grunt-autoprefixer');
    grunt.loadNpmTasks('grunt-contrib-uglify');
    grunt.loadNpmTasks('grunt-contrib-cssmin');
    grunt.registerTask('build', ['cssmin:minify', 'autoprefixer', 'uglify:compressjs']);
};