Gruntfile.js

module.exports = function ( grunt ) {
  
  /** 
   * Load required Grunt tasks. These are installed based on the versions listed
   * in `package.json` when you do `npm install` in this directory.
   */
  grunt.loadNpmTasks('grunt-contrib-clean');
  grunt.loadNpmTasks('grunt-contrib-copy');
  grunt.loadNpmTasks('grunt-contrib-concat');
  grunt.loadNpmTasks('grunt-contrib-watch');
  grunt.loadNpmTasks('grunt-contrib-less');
  grunt.loadNpmTasks('grunt-ng-annotate');
  grunt.loadNpmTasks('grunt-html2js');

  /**
   * Load in our build configuration file.
   */
  var userConfig = require( './build.config.js' );

  /**
   * This is the configuration object Grunt uses to give each plugin its 
   * instructions.
   */
  var taskConfig = {
    /**
     * We read in our `package.json` file so we can access the package name and
     * version. It's already there, so we don't repeat ourselves here.
     */
    pkg: grunt.file.readJSON("package.json"),


    /**
     * The directories to delete when `grunt clean` is executed.
     */
    clean: {
      build: ['<%= build_dir %>'],
      compile: ['<%= compile_dir %>']
    },

    /**
     * The `copy` task just copies files from A to B. We use it here to copy
     * our project assets (images, fonts, etc.) and javascripts into
     * `build_dir`, and then to copy the assets to `compile_dir`.
     */
    copy: {
      build_app_assets: {
        files: [
          { 
            src: [ '**' ],
            dest: '<%= build_dir %>/assets/',
            cwd: 'src/assets',
            expand: true
          }
       ]   
      },
      build_vendor_assets: {
        files: [
          { 
            src: [ '<%= vendor_files.assets %>' ],
            dest: '<%= build_dir %>/assets/',
            cwd: '.',
            expand: true,
            flatten: true
          }
       ]   
      },
      build_appjs: {
        files: [
          {
            src: [ '<%= app_files.js %>' ],
            dest: '<%= build_dir %>/',
            cwd: '.',
            expand: true
          }
        ]
      },
      build_vendorjs: {
        files: [
          {
            src: [ '<%= vendor_files.js %>' ],
            dest: '<%= build_dir %>/',
            cwd: '.',
            expand: true
          }
        ]
      },
      build_vendorcss: {
        files: [
          {
            src: [ '<%= vendor_files.css %>' ],
            dest: '<%= build_dir %>/',
            cwd: '.',
            expand: true
          }
        ]
      },
      compile_assets: {
        files: [
          {
            src: [ '**' ],
            dest: '<%= compile_dir %>/assets',
            cwd: '<%= build_dir %>/assets',
            expand: true
          },
          {
            src: [ '<%= vendor_files.css %>' ],
            dest: '<%= compile_dir %>/',
            cwd: '.',
            expand: true
          }
        ]
      }
    },

    /**
     * `grunt concat` concatenates multiple source files into a single file.
     */
    concat: {
      /**
       * The `build_css` target concatenates compiled CSS and vendor CSS
       * together.
       */
      build_css: {
        src: [
          '<%= vendor_files.css %>',
          '<%= build_dir %>/assets/<%= pkg.name %>-<%= pkg.version %>.css'
        ],
        dest: '<%= build_dir %>/assets/<%= pkg.name %>-<%= pkg.version %>.css'
      },
      /**
       * The `compile_js` target is the concatenation of our application source
       * code and all specified vendor source code into a single file.
       */
      compile_js: {
        src: [ 
          '<%= vendor_files.js %>', 
          'module.prefix', 
          '<%= build_dir %>/src/**/*.js', 
          '<%= html2js.common.dest %>',
          '<%= html2js.app.dest %>',
          'module.suffix' 
        ],
        dest: '<%= compile_dir %>/assets/<%= pkg.name %>-<%= pkg.version %>.js'
      }
    },


    /**
     * `ngAnnotate` annotates the sources before minifying. That is, it allows us
     * to code without the array syntax.
     */
    ngAnnotate: {
      compile: {
        files: [
          {
            src: [ '<%= app_files.js %>' ],
            cwd: '<%= build_dir %>',
            dest: '<%= build_dir %>',
            expand: true
          }
        ]
      }
    },

    /**
     * `grunt-contrib-less` handles our LESS compilation and uglification automatically.
     * Only our `main.less` file is included in compilation; all other files
     * must be imported from this file.
     */
    less: {
      build: {
        files: {
          '<%= build_dir %>/assets/<%= pkg.name %>-<%= pkg.version %>.css': '<%= app_files.less %>'
        }
      },
      compile: {
        files: {
          '<%= build_dir %>/assets/<%= pkg.name %>-<%= pkg.version %>.css': '<%= app_files.less %>'
        },
        options: {
          cleancss: true,
          compress: true
        }
      }
    },

    html2js: {
      /**
       * These are the templates from `src/app`.
       */
      app: {
        options: {
          base: 'src/app'
        },
        src: [ '<%= app_files.atpl %>' ],
        dest: '<%= build_dir %>/templates-app.js'
      },

      /**
       * These are the templates from `src/common`.
       */
      common: {
        options: {
          base: 'src/common'
        },
        src: [ '<%= app_files.ctpl %>' ],
        dest: '<%= build_dir %>/templates-common.js'
      }
    },

    /**
     * The `index` task compiles the `index.html` file as a Grunt template. CSS
     * and JS files co-exist here but they get split apart later.
     */
    index: {

      /**
       * During development, we don't want to have wait for compilation,
       * concatenation, minification, etc. So to avoid these steps, we simply
       * add all script files directly to the `<head>` of `index.html`. The
       * `src` property contains the list of included files.
       */
      build: {
        dir: '<%= build_dir %>',
        src: [
          '<%= vendor_files.js %>',
          '<%= build_dir %>/src/**/*.js',
          '<%= html2js.common.dest %>',
          '<%= html2js.app.dest %>',
          '<%= vendor_files.css %>',
          '<%= build_dir %>/assets/<%= pkg.name %>-<%= pkg.version %>.css'
        ]
      },

      /**
       * When it is time to have a completely compiled application, we can
       * alter the above to include only a single JavaScript and a single CSS
       * file. Now we're back!
       */
      compile: {
        dir: '<%= compile_dir %>',
        src: [
          '<%= concat.compile_js.dest %>',
          '<%= vendor_files.css %>',
          '<%= build_dir %>/assets/<%= pkg.name %>-<%= pkg.version %>.css'
        ]
      }
    },

    /**
     * And for rapid development, we have a watch set up that checks to see if
     * any of the files listed below change, and then to execute the listed 
     * tasks when they do. This just saves us from having to type "grunt" into
     * the command-line every time we want to see what we're working on; we can
     * instead just leave "grunt watch" running in a background terminal. Set it
     * and forget it, as Ron Popeil used to tell us.
     *
     * But we don't need the same thing to happen for all the files. 
     */
    delta: {
      /**
       * By default, we want the Live Reload to work for all tasks; this is
       * overridden in some tasks (like this file) where browser resources are
       * unaffected. It runs by default on port 35729, which your browser
       * plugin should auto-detect.
       */
      options: {
        livereload: true
      },

      /**
       * When the Gruntfile changes, we just want to lint it. In fact, when
       * your Gruntfile changes, it will automatically be reloaded!
       */
      gruntfile: {
        files: 'Gruntfile.js',
        tasks: [ 'jshint:gruntfile' ],
        options: {
          livereload: false
        }
      },

      /**
       * When our JavaScript source files change, we want to run lint them and
       * run our unit tests.
       */
      jssrc: {
        files: [ 
          '<%= app_files.js %>'
        ],
        tasks: [ 'copy:build_appjs' ]
      },

      /**
       * When assets are changed, copy them. Note that this will *not* copy new
       * files, so this is probably not very useful.
       */
      assets: {
        files: [ 
          'src/assets/**/*'
        ],
        tasks: [ 'copy:build_app_assets', 'copy:build_vendor_assets' ]
      },

      /**
       * When index.html changes, we need to compile it.
       */
      html: {
        files: [ '<%= app_files.html %>' ],
        tasks: [ 'index:build' ]
      },

      /**
       * When our templates change, we only rewrite the template cache.
       */
      tpls: {
        files: [ 
          '<%= app_files.atpl %>', 
          '<%= app_files.ctpl %>'
        ],
        tasks: [ 'html2js' ]
      },

      /**
       * When the CSS files change, we need to compile and minify them.
       */
      less: {
        files: [ 'src/**/*.less' ],
        tasks: [ 'less:build' ]
      }
    }
  };

  grunt.initConfig( grunt.util._.extend( taskConfig, userConfig ) );

  /**
   * In order to make it safe to just compile or copy *only* what was changed,
   * we need to ensure we are starting from a clean, fresh build. So we rename
   * the `watch` task to `delta` (that's why the configuration var above is
   * `delta`) and then add a new task called `watch` that does a clean build
   * before watching for changes.
   */
  grunt.renameTask( 'watch', 'delta' );
  grunt.registerTask( 'watch', [ 'build', 'delta' ] );

  /**
   * The default task is to build and compile.
   */
  grunt.registerTask( 'default', [ 'build', 'compile' ] );

  /**
   * The `build` task gets your app ready to run for development and testing.
   */
  grunt.registerTask( 'build', [
    'clean', 'html2js', 'less:build',
    'concat:build_css', 'copy:build_app_assets', 'copy:build_vendor_assets',
    'copy:build_appjs', 'copy:build_vendorjs', 'copy:build_vendorcss', 'index:build'
  ]);

  /**
   * The `compile` task gets your app ready for deployment by concatenating and
   * minifying your code.
   */
  grunt.registerTask( 'compile', [
    'less:compile', 'copy:compile_assets', 'ngAnnotate', 'concat:compile_js', 'index:compile', 'clean:build'
  ]);

  /**
   * A utility function to get all app JavaScript sources.
   */
  function filterForJS ( files ) {
    return files.filter( function ( file ) {
      return file.match( /\.js$/ );
    });
  }

  /**
   * A utility function to get all app CSS sources.
   */
  function filterForCSS ( files ) {
    return files.filter( function ( file ) {
      return file.match( /\.css$/ );
    });
  }

  /** 
   * The index.html template includes the stylesheet and javascript sources
   * based on dynamic names calculated in this Gruntfile. This task assembles
   * the list into variables for the template to use and then runs the
   * compilation.
   */
  grunt.registerMultiTask( 'index', 'Process index.html template', function () {
    var dirRE = new RegExp( '^('+grunt.config('build_dir')+'|'+grunt.config('compile_dir')+')\/', 'g' );
    var jsFiles = filterForJS( this.filesSrc ).map( function ( file ) {
      return file.replace( dirRE, '' );
    });
    var cssFiles = filterForCSS( this.filesSrc ).map( function ( file ) {
      return file.replace( dirRE, '' );
    });

    grunt.file.copy('src/index.html', this.data.dir + '/index.html', { 
      process: function ( contents, path ) {
        return grunt.template.process( contents, {
          data: {
            scripts: jsFiles,
            styles: cssFiles,
            version: grunt.config( 'pkg.version' )
          }
        });
      }
    });
  });

};