javascript语法？ES6语法？

悬赏园豆：5 [待解决问题]

  setMarks(Json) {
      const result = Json.reduce((arr, it) => {
        arr.push({
          id: it.id,
          name: it.IPBoxName,
          addr: it.IPBoxAddr,
          lnglat: [+it.Lng, +it.Lat],
          color: {
            0: `rgba(165,165,165, .4)`,
            1: `rgba(66,185,131, .4)`,
            2: `rgba(244,81,108, .4)`,
            3: `rgba(244,81,108, .4)`,
            4: `rgba(144,144,144, .4)`
          }[it.status],
          type: 'circle',
          speed: 0.5
        })
        return arr
      }, [])

中

          color: {
            0: `rgba(165,165,165, .4)`,
            1: `rgba(66,185,131, .4)`,
            2: `rgba(244,81,108, .4)`,
            3: `rgba(244,81,108, .4)`,
            4: `rgba(144,144,144, .4)`
          }[it.status],

根据status的值跟0~4进行匹配，选择对应颜色存入color，请问这是属于javascript的什么语法？网上查了很久没查到

javascript语法