components_play.html

<template>
  <view class="container">

    <view>
      <view>
        父组件
      </view>
      <view>
        {{ data.today.format('YYYY-MM-DD') }}
      </view>
      <view>
        {{ today.format('YYYY-MM-DD') }}
      </view>
      <view>
        {{ formatted }}
      </view>
    </view>

    <play :data="data" :today="today" :formatted="formatted" />
  </view>
</template>

<style></style>

<script>
  import play from '../components/play'
  import dayjs from 'dayjs'

  export default {
    components: {
      play,
    },

    data() {
      return {
        today: dayjs('2018-09-28'),
        formatted: '2018-09-28',
        data: {
          today: dayjs('2018-09-28')
        },
      };
    },

    mounted() {
        console.log('delay change state')
        this.data = {today: dayjs('2018-10-08')}
        this.today = dayjs('2018-10-08')
        this.formatted = '2018-10-08'
    },

    methods: {
    },
  };
</script>

pages_playground.html

<template>
  <view class="container">

    <view>
      <view>
        父组件
      </view>
      <view>
        {{ data.today.format('YYYY-MM-DD') }}
      </view>
      <view>
        {{ today.format('YYYY-MM-DD') }}
      </view>
      <view>
        {{ formatted }}
      </view>
    </view>

    <play :data="data" :today="today" :formatted="formatted" />
  </view>
</template>

<style></style>

<script>
  import play from '../components/play'
  import dayjs from 'dayjs'

  export default {
    components: {
      play,
    },

    data() {
      return {
        today: dayjs('2018-09-28'),
        formatted: '2018-09-28',
        data: {
          today: dayjs('2018-09-28')
        },
      };
    },

    mounted() {
        console.log('delay change state')
        this.data = {today: dayjs('2018-10-08')}
        this.today = dayjs('2018-10-08')
        this.formatted = '2018-10-08'
    },

    methods: {
    },
  };
</script>