Gruntfile.js

// The wrapper function
module.exports = function (grunt) {

    // Project and task configuration
    grunt.initConfig({
        concat: {
            options: {
                separator: "\n\n"
            },
            dist: {
                src: [
                    'app/js/app.js'
                ],
                dest: 'environments/dev/web/js/main.js'
            }
        },
        copy: {
            styles: {
                files: [
                    {
                        cwd: 'environments/dev/web/css/',
                        expand: true,
                        filter: 'isFile',
                        src: ['**/*.css'],
                        dest: 'web/css/'
                    }
                ]
            },
            scripts: {
                files: [
                    {
                        cwd: 'environments/dev/web/js/',
                        expand: true,
                        filter: 'isFile',
                        src: ['**/*.js'],
                        dest: 'web/js/'
                    }
                ]
            }
        },
        less: {
            dev: {
                files: {
                    "environments/dev/web/css/main.css": "app/less/main.less",
                    "environments/dev/web/css/responsive.css": "app/less/responsive.less"
                }
            },
            prod: {
                options: {
                    compress: true,
                    yuicompress: true,
                    optimization: 2
                },
                files: {
                    "environments/prod/web/css/main.css": "app/less/main.less",
                    "environments/prod/web/css/responsive.css": "app/less/responsive.less"
                }
            }
        },
        watch: {
            styles: {
                files: [
                    'app/less/**/*.less',
                    'web/css/**/*.css' // handle css file deletion as well
                ],
                tasks: ['less', 'copy'],
                options: {
                    livereload: 1337,
                    nospawn: true
                }
            },
            scripts: {
                files: ['app/js/**/*.js'],
                tasks: ['concat', 'copy'],
                options: {
                    // Start a live reload server on the default port 35729
                    livereload: true,
                    nospawn: true
                }
            }
        }
    });

    // Load plugins
    grunt.loadNpmTasks('grunt-closure-compiler');
    grunt.loadNpmTasks('grunt-contrib-concat');
    grunt.loadNpmTasks('grunt-contrib-copy');
    grunt.loadNpmTasks('grunt-contrib-less');
    grunt.loadNpmTasks('grunt-contrib-watch');

    // Define tasks
    grunt.registerTask('default', ['watch']);
    grunt.registerTask('compile-js', ['closure-compiler', 'copy']);

};