momentjs操作上一天下一天

data() {
    return {
      nowDate: new Date()
    }
  },
methods:{
    lastDay() {
      let start = moment(this.nowDate)
      this.nowDate = moment(start).subtract(1, 'day')
    },
    nextDay() {
      let start = moment(this.nowDate)
      this.nowDate = moment(start).add(1, 'day')
    },
}