Excerpt of Grunt file needed to concat CSS and JS files

build-config

  grunt.registerTask('build', [
    'clean:dist',
    'copy',
    'useminPrepare',
    'concat',
    'string-replace',
  ]);

Gruntfile.js

    // Reads HTML for usemin blocks to enable smart builds that automatically
    // concat, minify and revision files. Creates configurations in memory so
    // additional tasks can operate on them
    useminPrepare: {
      html: '<%= yeoman.app %>/index.html',
      options: {
        dest: '<%= yeoman.dist %>',
        flow: {
          html: {
            steps: {
              js: ['concat'],
              css: ['concat']
            },
            post: {}
          }
        }
      }
    },

    // Copies remaining files to places other tasks can use
    copy: {
      dist: {
        files: [{
          expand: true,
          dot: true,
          cwd: '<%= yeoman.app %>',
          dest: '<%= yeoman.dist %>',
          src: [
            'views/{,*/}*.html',
          ]
        }]
      },
      styles: {
      }
    },

    // add description label of the final result
    concat: {
      options: {
        banner: '/* <%= yeoman.name %> - v<%= yeoman.version %> - ' + '<%= grunt.template.today("yyyy-mm-dd") %> */\n\n'
      }
    },

    // replace pieces of string
    'string-replace': {
      dist: {
        files: {
          './': 'dist/**/*.*'
        },
        options: {
          replacements: [{
            pattern: /views\/templates\/default\.html/g,
            replacement: 'bower_components/<%= yeoman.name %>/dist/views/templates/default.html'
          }]
        }
      }
    }