Syntax error using a mask passed inside a v-model object

[PloggCTO]

I have detailed my question on stackoverflow:
https://stackoverflow.com/questions/77901213/cannot-assign-object-property-to-vue-3-directive-using-dynamic-key

Basically, this works:

<script setup>
  const mask = ref({ mask: "####" });
</script>

<template>
  <v-input-field v-maska:[mask] />
</template>

But this gives a syntax error on the v-maska line:
Error parsing JavaScript expression: Unexpected token, expected "]"

Data passed as model:

<script setup>
  import MyForm from"@/components/my-form.vue";
  
  const form = ref([
    num: {
      mask: "####"
    }
  ]);
</script>

<template>
  <my-form v-model="form" />
</template>

And the code:

<script setup>
  const model = defineModel({ type: Object });
  const mask = ref({ mask: "####" });
</script>

<template>
  <div v-for="field in Object.keys(model)" :key="field">
    <v-input-field
      v-model="model[field].value"
      v-maska:[model[field].mask]
    />
  </div>
</template>

[PloggCTO]

Is it because I am using an array index inside a directive [ ] ?

[PloggCTO]

Answer in the stack overflow post.