refactor(VDateInput): If multiple, reset model to []

[ikushum]

Description

In multiple mode, when the date is reset/cleared, we should set the model value to [] instead of null

Why is this change required?

In multiple mode, the model value is expected to be an array. Setting it to null would break the expected type.

What problem does it solve?

The change ensures consistent behavior when date is reset/cleared and maintains the correct type for the model value.

Markup:

<template>
  <v-app>
    <v-container>
      {{ date }}
      <v-date-input
        v-model="date"
        clearable
        multiple="range"
        @update:model-value="onUpdateModelValue"
      />
    </v-container>
  </v-app>
</template>

<script setup>
  import { ref } from 'vue'

  const date = ref([])
</script>

[johnleider]

This is what I'm working on https://github.com/vuetifyjs/vuetify/pull/21055/files#diff-7f8c8d50ea1b2e7d7e521fcddcaf3e22e82955a715984dba14781eaf8c04910b for. We need a more homogenized way to do this.

[J-Sek]

@johnleider I agree we need similar thing in VSelect, VCombobox, VAutocomplete and probably VFileInput as well, but #21055 goes too far. I have poked it a bit, forced the prop to be a function, but could not force VTextField to emit [] (it is designed to emit string | null). I think it is not the responsibility of VTextField to execute the clearValue().

[ikushum]

This is what I'm working on #21055 (files) for. We need a more homogenized way to do this.

The prop clear-value is a good "nice to have" feature but even without the prop the components should reset to correct value.