code: function () {
  
          var files = [];
          var combo = '';
          var cache = this._getCache();
          var code = '';
          var build = Date.now();
  
          for (var i in cache) {
  
              code = cache[i];
              code = this._removeMetadata(code);
              combo += code;
  
              files.push(i);
          }
  
  
          var metadata = {};
          if (this.options.debug) {
              metadata.debug = true;
          }
  
          if (this.options.combo) {
              metadata.version = this.projectVersion;
          }
  
  
          this._buildRuntime(combo, metadata, function (error, data) {
  
              // 广播：合并事件
              this.emit('combo', error, {
  
                  // 编译时间
                  build: build,
  
                  // 打包的代码
                  output: data,
  
                  // 输出的文件路径
                  outputFile: this.runtime,
  
                  // 被合并的文件列表
                  sourcefiles: files
  
              });
  
          });
  
      }
docs: 打包模板