docs: function compress(file) {
    var ext = path.extname(file),
      res,
      source,
      result;
  
    switch (ext) {
      case '.js':
        console.log('uglifying js file ' + file);
  
        res = ngAnnotate(String(fs.readFileSync(file, 'utf8')), {
          add: true
        });
        result = UglifyJS.minify(res.src, hookConfig.uglifyJsOptions);
        fs.writeFileSync(file, result.code, 'utf8'); // overwrite the original unminified file
        break;
  
      case '.css':
        console.log('minifying css file ' + file);
  
        source = fs.readFileSync(file, 'utf8');
        result = cssMinifier.minify(source);
        fs.writeFileSync(file, result.styles, 'utf8'); // overwrite the original unminified file
        break;
  
      default:
        console.log('encountered a ' + ext + ' file, not compressing it');
        break;
    }
  }