Query relationship with v-autocomplete in Vuetify [ Laravel ] - laravel

Question

I use dropdown v-autocomplete in Vuetify and i want to query relationship from laravel. When select in input field in v-autocomplete, its work well, its show name that i want to query, but when i selected on it, it show to default value.
Here my Vuetify
<template>
<v-autocomplete
:items="purchases"
dense
solo
v-model="model"
item-text="name"
item-value="name"
return-object
clearable
#input="addTocart"
>
<template v-slot:item="{ item }">
{{ item.product.name }}
</template>
</v-autocomplete>
</template>
In my script
<script>
export default {
name: 'Add Purchase',
created() {
this.fetchPurchase()
},
data() {
return {
products: [],
purchases: [],
model: [],
items: [],
purchase_status: ['Received', 'Partial', 'Pending', 'Ordered'],
discount: 0.00,
tax: 0.00,
shipping_cost: 0.00,
}
},
computed: {
total() {
return this.products.reduce((total, item) => {
return total + item.unit;
}, 0);
}
},
methods: {
fetchPurchase() {
this.$axios.$get(`api/purchase`)
.then(res => {
this.purchases = res.data;
console.log(res);
})
.catch(err => {
console.log(err)
})
},
addTocart (item) {
if(this.items.includes(item)) {
alert("already there");
}else {
this.items.push(item);
}
item.unit = 1;
},
removeItem(index) {
this.items.splice(index, 1)
},
}
}
</script>
Is there a way that i can archieve this? Thanks in advance..