docs: function initSASS() {
    var sassMap = build.engine.sass.map;
    var opt = {
      src: build.sourceDir,
      // Recompile on every request.
      force: true,
      // Write the .css file, do not stream it.
      response: false,
      // Configure source maps.
      sourceMap: sassMap.enabled,
      sourceMapEmbed: sassMap.inline
    };
    // Handle the .sass file extension.
    var sassOpt = lodash.assign({ indentedSyntax: true }, opt);
    app.use(sassMw(sassOpt));
    // Handle the .scss file extension.
    var scssOpt = lodash.assign({ indentedSyntax: false }, opt);
    app.use(sassMw(scssOpt));
  }