VueJs OnMount props generate “Expected Object, got Undefined ” warning

I’ve got the following component:

<template>
  <Grid :items="items" />
</template>

<script setup>
  import { ref, onMounted } from 'vue'
  import Grid from '@/components/Grid.vue'
  import { getData } from '@/services/getData'

  const items = ref()

  onMounted(async () => {
    items.value = await getData()
 })
</script>

The Grid component instance needs items to be populated in order to display data, but I need to run getData() to have the data ready. When I run this code I get a type check failed for prop "items". Expected Object, got Undefined warning.

It happens because when the file is first initiated items doesn’t have anything until getData() is finished. How can I have getData() run before the warning can show up?