echarts设置option中的数据对象优化

if(tab.name == 'first'){
          myChart.setOption({
            legend: {
            selected:{
              [this.playNumber]:true,
              [this.coverNumber]:false,
              [this.touchNumber]:false,
              [this.winPrizeNum]:false,
              [this.takePrizeNum]:false
            }
        },

          })
      }else if(tab.name == 'second'){
          myChart.setOption({
            legend: {
              selected:{
              [this.playNumber]:false,
              [this.coverNumber]:true,
              [this.touchNumber]:false,
              [this.winPrizeNum]:false,
              [this.takePrizeNum]:false
             }
            },
          })
      }else if(tab.name == 'third'){
          myChart.setOption({
            legend: {
              selected:{
                [this.playNumber]:false,
                [this.coverNumber]:false,
                [this.touchNumber]:true,
                [this.winPrizeNum]:false,
                [this.takePrizeNum]:false
              }
            },
          })
      }else if(tab.name == 'fourth'){
          myChart.setOption({
            legend: {
              selected:{
                [this.playNumber]:false,
                [this.coverNumber]:false,
                [this.touchNumber]:false,
                [this.winPrizeNum]:true,
                [this.takePrizeNum]:false
              }
            }
          })
      }else if(tab.name == 'five'){
          myChart.setOption({
            legend: {
              selected:{
                [this.playNumber]:false,
                [this.coverNumber]:false,
                [this.touchNumber]:false,
                [this.winPrizeNum]:false,
                [this.takePrizeNum]:true
              }
            }
          })
      }

　　代码优化：

var arr = {'first':[this.playNumber],'second':[this.coverNumber],'third':[this.touchNumber],'fourth':[this.winPrizeNum],'five':[this.takePrizeNum]};
      var obj = {
          [this.playNumber]:false,
          [this.coverNumber]:false,
          [this.touchNumber]:false,
          [this.winPrizeNum]:false,
          [this.takePrizeNum]:false
      };
      Object.keys(arr).forEach(function(key){
        if(tab.name == key){
          obj[arr[key]] = true;
        }
      });
      myChart.setOption({
        legend: {
          selected: obj
        },
      });