Parses the index.html file to determine which JS and CSS files to concatenate

gruntfile.js

module.exports = function( grunt )
{
    grunt.initConfig({
        //Create jsResources and cssResources configuration properties
        jsResources: [],
        cssResources: [],

        clean: {
            build: {
                dot: true,
                src: [ '../build/**/*' ]
            }

        },

        copy: {
            build: {
                files: [
                    {
                        cwd: '../app/',
                        dest: '../build/',
                        expand: true,
                        //Copy over the index.html file and all the files in the "views" directory
                        src: [ 'index.html', 'views/**' ]
                    }
                ]
            }
        },

        replace: {
            gather: {
                files: [
                    {
                        cwd: '../app/',
                        dest: '../build/',
                        expand: true,
                        src: [ 'index.html' ]
                    }
                ],
                options: {
                    patterns: [
                        {
                            //Grab the <!--build-js-start--> and <!--build-js-end--> comments and everything in-between
                            match: /\<\!\-\-build\-js\-start[\s\S]*build\-js\-end\-\-\>/,
                            replacement: function ( matchedString ) {
                                //Grab all of the src attributes from the <script> tags
                                var jsArray = matchedString.match( /(src\s?\=\s?[\'\"])([^\'\"]*)([\'\"])/g );
                                jsArray.forEach( function( element ) {
                                    //Get just the value of the src attribute (the file path to the JS file)
                                    var resourceTarget = element.match( /(src\s?\=\s?[\'\"])([^\'\"]*)([\'\"])/ )[ 2 ];
                                    targetConfig = grunt.config( 'jsResources' );
                                    //Alter the path for use with the concat task
                                    targetConfig.push( '../app/' + resourceTarget );
                                    //Add the path to the JS file to the jsResources configuration property
                                    grunt.config( 'jsResources', targetConfig );
                                });

                                //Replace the entire build-js-start to build-js-end block with this <script> tag
                                return '<script type="text/javascript" src="combined.js"></script>';
                            }
                        },
                        {
                            //Grab the <!--build-css-start--> and <!--build-css-end--> comments and everything in-between
                            match: /\<\!\-\-build\-css\-start[\s\S]*build\-css\-end\-\-\>/,
                            replacement: function ( matchedString ) {
                                //Grab all of the href attributes from the <href> tags
                                var cssArray = matchedString.match( /(href\s?\=\s?[\'\"])([^\'\"]*)([\'\"])/g );
                                cssArray.forEach( function( element ) {
                                    var resourceTarget = element.match( /(href\s?\=\s?[\'\"])([^\'\"]*)([\'\"])/ )[ 2 ];
                                    var targetConfig = grunt.config( 'cssResources' );
                                    //Alter the path for use with the concat task
                                    targetConfig.push( '../app/' + resourceTarget );
                                    //Add the path to the CSS file to the cssResources configuration property
                                    grunt.config( 'cssResources', targetConfig );
                                });

                                //Replace the entire build-css-start to build-css-end block with this <link> tag
                                return '<link rel="stylesheet" media="screen" href="combined.css"/>';
                            }
                        }
                    ]
                }
            }
        },

        concat: {
            js: {
                //Concatenate all of the files in the jsResources configuration property
                src: [ '<%= jsResources %>' ],
                dest: '../build/combined.js',
                options: {
                    separator: ';'
                }
            },

            css: {
                //Concatenate all of the files in the cssResources configuration property
                src: [ '<%= cssResources %>' ],
                dest: '../build/combined.css'
            }

        }

    });

    grunt.loadNpmTasks( 'grunt-contrib-clean' );
    grunt.loadNpmTasks( 'grunt-contrib-concat' );
    grunt.loadNpmTasks( 'grunt-contrib-copy' );
    grunt.loadNpmTasks( 'grunt-replace' );

    grunt.registerTask( 'build', 'Creates a build from the files in the app directory', function() {
        //So the user doesn't have to add '--force' to the command to clean the build directory
        grunt.option( 'force', true );

        grunt.task.run ( [
            'clean:build',
            'copy:build',
            'replace:gather',
            'concat:css',
            'concat:js'
        ]);

    });

};