获取上一月份

方法1： //当前月份上一个月

 getLastMonth() {
  
      let currentDate = new Date();
      let last_month = currentDate.getMonth() - 1;
      if (last_month < 0) {
        currentDate.setMonth(11);
      } else if (last_month == 0) {
        currentDate.setMonth(0);
      } else {
        currentDate.setMonth(last_month);
      }
      this.query.time = currentDate;
    },

方法2：

const getHandledValue = num => {
    return num < 10 ? '0' + num : num
}


const getNowMonth = () => {
    const date = new Date()
    const year = date.getFullYear()
    const month = getHandledValue(date.getMonth() + 1)
    const nowMonth = year + "-" + month
    return nowMonth
}

export const getPreMonth = () => {
    const arr = getNowMonth().split("-")
    const year = arr[0]
    const month = arr[1]
    let year2 = year
    let month2 = parseInt(month) - 1
    if (month2 == 0) {
        year2 = parseInt(year2) - 1
        month2 = 12
    }
    if (month2 < 10) {
        month2 = "0" + month2
    }
    const preMonth = year2 + "-" + month2
    return preMonth
}