如果为value=null，则Vue3js Cutom输入组件将消失

import { defineComponent, ref, watch } from 'vue';

export default defineComponent({
  props: {
    value: {
      type: null,
      default: null
    }
  },
  emits: ['update:value'],
  setup(props, { emit }) {
    const inputValue = ref(props.value);

    watch(inputValue, (newValue) => {
      emit('update:value', newValue);
    });

    return {
      inputValue
    };
  }
});

<template>
  <div>
    <custom-input v-model="inputValue"></custom-input>
  </div>
</template>

<script>
import CustomInput from './CustomInput.vue';

export default {
  components: {
    CustomInput
  },
  data() {
    return {
      inputValue: null
    };
  }
};
</script>