实现效果:

代码：

引入momentjs然后封装两个函数构建出基本数据结构

import moment from 'moment';

// 某月有多少天
export const getEndDay = (m) => m.daysInMonth();

/**
 * @description 获取本月空值数据
 *  @param { Date } year {  } 年度
 *  @param { Number } month 月份
 *  @param { Date } current moment当天日期
 */
export const getCalendar = ({ year, month, current }) => {
  // 最多6行, 每行为一周7天
  const totalDays = 7 * 6;
  // 获取这个月第一天具体日期
  const start = new Date(year, month - 1, 1);

  let lastEndDay = [];
  // 上个月的天数
  const lastDays = getEndDay(current.clone().subtract(1, 'month'));
  // 当前月的天数
  const nowDays = getEndDay(current);
  const currentDays = [...(new Array(nowDays))].map((v, i) => ({
    day: i + 1,
  })).map((v) => {
    const currentDate = v.day >= 10 ? `${moment(current).format('YYYY-MM')}-${v.day}` : `${moment(current).format('YYYY-MM')}-0${v.day}`;
    return {
      day: v.day,
      denyTime: moment().valueOf() > moment(`${currentDate} 23:59:59`).valueOf(),
      currentDate,
    };
  });
  if (start.getDay() === 0) {
    // 这个月1号为周日，则取上个月最后6天
    lastEndDay = [...new Array(lastDays)].map((v, i) => i + 1).filter((v) => v > lastDays - 6).map((v) => ({
      day: v,
      denyMonth: true,
    }));
  } else {
    lastEndDay = [...(new Array(lastDays))].map((v, i) => i + 1).filter((v, i) => i  > lastDays - start.getDay()).map((v) => ({
      day: v,
      denyMonth: true,
    }));
  }
  // 获取下个月补充天数
  const nextDays = [...new Array(totalDays - lastEndDay.length - currentDays.length)].map((v, i) => ({ day: i + 1, denyMonth: true }));
  const data = [...lastEndDay, ...currentDays, ...nextDays];
  return data;
};

页面代码部分:

<template>
  <div>
    <div class="flex-y-center flex-x-between border-t border-r border-l pad-y-xs pad-x-md">
            <div>{{ renderCalendarMonth }}</div>
            <div class="text-right">
              <el-button size="small" @click="handleMonth(1)">上个月</el-button>
              <el-button size="small" @click="handleMonth()">本月</el-button>
              <el-button size="small" @click="handleMonth(2)">下个月</el-button>
            </div>
          </div>
          <div class="border-a pad-a-sm">
            <div class="grid-week mar-b-sm">
              <div v-for="item in weekLabel" :key="item" class="text-center">
                {{ item }}
              </div>
            </div>
            <div class="grid-month-day">
              <div
                v-for="(item, idx) in CalendarDays"
                :key="idx"
                :class="{
                  'text-center': 1,
                  'grey-out-ban': item.denyMonth || item.denyTime,
                  'active': item.currentDate === activeDay
                }"
                @click="handleDay(item)"
              >
                {{ item.day }}
              </div>
            </div>
          </div>
</div>
</template>

import moment from 'moment';
import { getCalendar } from '../request';

export default {
 data() {
    return {
      weekLabel: ['一', '二', '三', '四', '五', '六', '七'],
      // 当前时间日历推导
      currentTime: moment(),
      // 日历挂表
      CalendarDays: [],
      // 选择日期
      activeDay: moment().format('yyyy-MM-DD'),
      // 月份切换
      activeMonth: 0,
    };
  },
computed: {
    // 日历具体年月份
    renderCalendarMonth() {
      const enumMonth = ['一', '二', '三', '四', '五', '六', '七', '八', '九',  '十', '十一', '十二'];
      const year = moment().subtract(this.activeMonth, 'months').format('yyyy');
      let month = moment().subtract(this.activeMonth, 'months').format('M');
      month = enumMonth[month - 1];
      return `${year}年${month}月`;
    },
  },
created() {
    this.init();
  },
  methods: {
    // 初始化
    init() {
      this.CalendarDays = getCalendar({
        year: moment().format('yyyy'), current: this.currentTime, month: moment().format('M'),
      });
    },
    // 月份切换
    handleMonth(type) {
      if (type) {
        if (type === 1) {
          this.activeMonth++;
        } else {
          this.activeMonth--;
        }
        const day = moment().subtract(this.activeMonth, 'months');
        this.CalendarDays = getCalendar({
          year: day.format('yyyy'),
          current: day,
          month: day.format('M'),
        });
      } else {
        this.activeMonth = 0;
        this.CalendarDays = getCalendar({
          year: moment().format('yyyy'), current: this.currentTime, month: moment().format('M'),
        });
        this.activeDay = moment().format('yyyy-MM-DD');
      }
    },
    handleDay(item) {
      if (item.denyMonth || item.denyTime) return;
      this.activeDay = item.currentDate;
    },
  },


};
</script>

<style lang="scss" scoped>
.grid-week, .grid-month-day {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 10px;
}

.grid-month-day {
  &>div {
    padding: 6px 0;
    box-sizing: border-box;
    border: 1px solid $base-border-color;
    &.grey-out-ban {
      background-color: #E9E9EB;
      cursor: not-allowed;
    }
    &:not(.grey-out-ban) {
      color: $base-color-primary;
      cursor: pointer;
    }
    &.active {
      border: 1px solid $base-color-primary;
      background-color: $base-color-primary;
      color: white;
    }
  }
}
</style>

---

结尾：这里贴代码就挺难受的，没有Vue只有html，果然这个时候用react就不错，不过思路已经提供了，先理清日历的每周对应天数结构，后面处理起来就容易许多。这里附上做的另一个日历效果图，代码就不贴了，js推导函数都差不多，不过是把日期天数的推导改下就可以了。