Я добавил исправления в приведенную выше логику, которую вы пытаетесь
Найдите рабочий код здесь: https://codepen.io/chansv/pen/yLLbZWo?editors=1010
<div id="app">
<v-app id="inspire">
<v-data-table
:headers="headers"
:items="desserts"
:single-expand="singleExpand"
:expanded.sync="expanded"
item-key="name"
show-expand
class="elevation-1"
>
<template v-slot:top>
<v-toolbar flat color="white">
<v-toolbar-title>Expandable Table</v-toolbar-title>
<v-spacer></v-spacer>
<v-switch v-model="singleExpand" label="Single expand" class="mt-2"></v-switch>
</v-toolbar>
</template>
<template v-slot:expanded-item="{ headers }">
<td :colspan="headers.length">
<v-simple-table>
<template v-slot:default>
<thead>
<tr>
<th>Dessert (400g serving)</th>
<th>Calories</th>
<th>Fat</th>
<th>Carbs</th>
<th>Protein</th>
<th>Iron</th>
</tr>
</thead>
<tbody>
<tr v-for="dessert in desserts" :key="dessert.name">
<td>{{ dessert.name }}</td>
<td>{{ dessert.calories * 4 }}</td>
<td>{{ dessert.fat * 4 }}</td>
<td>{{ dessert.carbs * 4 }}</td>
<td>{{ dessert.protein * 4 }}</td>
<td>{{ '4%' }}</td>
</tr>
</tbody>
</template>
</v-simple-table>
</td>
</template>
</v-data-table>
</v-app>
</div>
new Vue({
el: '#app',
vuetify: new Vuetify(),
data () {
return {
expanded: [],
singleExpand: false,
headers: [
{
text: 'Dessert (100g serving)',
align: 'left',
sortable: false,
value: 'name',
},
{ text: 'Calories', value: 'calories' },
{ text: 'Fat (g)', value: 'fat' },
{ text: 'Carbs (g)', value: 'carbs' },
{ text: 'Protein (g)', value: 'protein' },
{ text: 'Iron (%)', value: 'iron' },
{ text: '', value: 'data-table-expand' },
],
desserts: [
{
name: 'Frozen Yogurt',
calories: 159,
fat: 6.0,
carbs: 24,
protein: 4.0,
iron: '1%',
},
{
name: 'Ice cream sandwich',
calories: 237,
fat: 9.0,
carbs: 37,
protein: 4.3,
iron: '1%',
},
{
name: 'Eclair',
calories: 262,
fat: 16.0,
carbs: 23,
protein: 6.0,
iron: '7%',
},
{
name: 'Cupcake',
calories: 305,
fat: 3.7,
carbs: 67,
protein: 4.3,
iron: '8%',
},
{
name: 'Gingerbread',
calories: 356,
fat: 16.0,
carbs: 49,
protein: 3.9,
iron: '16%',
},
{
name: 'Jelly bean',
calories: 375,
fat: 0.0,
carbs: 94,
protein: 0.0,
iron: '0%',
},
{
name: 'Lollipop',
calories: 392,
fat: 0.2,
carbs: 98,
protein: 0,
iron: '2%',
},
{
name: 'Honeycomb',
calories: 408,
fat: 3.2,
carbs: 87,
protein: 6.5,
iron: '45%',
},
{
name: 'Donut',
calories: 452,
fat: 25.0,
carbs: 51,
protein: 4.9,
iron: '22%',
},
{
name: 'KitKat',
calories: 518,
fat: 26.0,
carbs: 65,
protein: 7,
iron: '6%',
},
],
}
},
})