获取年月YYYY-MM

 setDefaultValues() {
      return new Promise(resolve => {
        const year = moment().year()
        // moment月份范围是 0~11, 默认设置为上个月, 不需要 -1
        let month = moment().month()
        if (month === 0) {
          month = 12
        }
        this.defaultMonth = moment(`${year}-${month}`, 'YYYY-MM') 
          this.queryParam.lineId = 41
        this.queryParam.date = this.defaultMonth.format('YYYY-MM')

        resolve()
      })
    },