docs: function minifyApp(appNameMap, appContentMap) {
    let file = config.distDir + 'app.wxss';
    if (!utils.isFile(file)) {
      return;
    }
    let minified = new CleanCSS({ keepBreaks: true }).minify(fs.readFileSync(file, 'utf8')).styles;
    minified = minified.replace(/::?(after|before|first\-child|last\-child)/g, ':$1');
    let finalCssContent = '';
    minified.split('\n').forEach((line) => {
      let index = line.indexOf('{');
      let selectors = line.substr(0, index).split(',');
      let content = line.substr(index);
  
      selectors.forEach((selector) => {
        if (selector[0] !== '.') {
          finalCssContent += selector + content + '\n';
          return;
        }
        let className = selector.substr(1);
        if (!appNameMap[className]) {
          appNameMap[className] = {
            id: '',
            contents: []
          };
        }
        appNameMap[className].contents.push(content);
        if (!appContentMap[content]) {
          appContentMap[content] = [];
        }
        appContentMap[content].push(className);
      });
    });
  
    return function () {
      //console.log(appNameMap, appContentMap);
      console.log('minify'.green, path.normalize('dist/app.wxss').blue);
      for (let key in appNameMap) {
        let matchs = key.match(/(.*):+(after|before|first\-child|last\-child)$/);
        if (matchs && appNameMap[matchs[1]] && appNameMap[matchs[1]].id) {
          appNameMap[key].id = appNameMap[matchs[1]].id + ':' + matchs[2];
        }
      }
      for (let c in appContentMap) {
        let keys = [];
        appContentMap[c].forEach((key) => {
          if (appNameMap[key].id) {
            keys.push('.' + appNameMap[key].id);
            console.log(('\t.' + key).blue, '->', ('.' + appNameMap[key].id).cyan);
          } else if (config.classNames && config.classNames[key]) {
            keys.push('.' + key);
            console.log(('\t.' + key).blue, '->', ('.' + key).cyan);
          }
        });
        if (keys.length) {
          finalCssContent += keys.join(',') + c + '\n';
        }
      }
      finalCssContent = new CleanCSS({ keepBreaks: true }).minify(finalCssContent).styles;
      fs.writeFileSync(file, finalCssContent);
    };
  }