vue.js v-for on two table rows

Question

Vue 2, no webpack. I want to render two trs at a time, for main and detail expandable row. This is what I'm trying to achieve:

<table>
   <tbody>
     <div v-for="item in items">
         <tr></tr>
         <tr class="detail-row"></tr>
     </div>
   </tbody>
</table>

The problem is that <div> is an invalid child of tbody. How to render two <tr>s at each for loop iteration?

Answer 1

This is the way you solve it in browsers that support template.

<table>
   <tbody>
     <template v-for="item in items">
         <tr></tr>
         <tr class="detail-row"></tr>
     </template>
   </tbody>
</table>

If you need to support browsers that do not support template, I typically resort to a render function.

Here is a working example of both.

console.clear()

new Vue({
  el: "#app",
  data: {
    items: [{
        master: "Master",
        detail: "Detail"
      },
      {
        master: "Master",
        detail: "Detail"
      },
    ]
  }
})

new Vue({
  el: "#app2",
  data: {
    items: [{
        master: "Master",
        detail: "Detail"
      },
      {
        master: "Master",
        detail: "Detail"
      },
    ]
  },
  render(h){
    // build the rows
    let rows = []
    for (let item of this.items){
      rows.push(h("tr", [h("td", [item.master])]))
      rows.push(h("tr", {class: "detail-row"}, [h("td", [item.detail])]))
    }
    
    // add rows to body
    let body = h("tbody", rows)
    
    // return the table
    return h("table", [body])
  }
})

.detail-row{
 background-color: lightgray;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.13/vue.js"></script>

<h2>Using template</h2>
<div id="app">
  <table>
    <tbody>
      <template v-for="item in items">
        <tr><td>{{item.master}}</td></tr>
        <tr class="detail-row"><td>{{item.detail}}</td></tr>
      </template>
    </tbody>
  </table>
</div>
  
<h2>Using render function</h2>
<div id="app2"></div>

Answer 2

In newer version of VueJS, it wants an index. So the solution would look like

  <table>
    <tbody>
      <template v-for="(item, index) in items">
        <tr :key="index">
           <td>{{item.master}}</td>
        </tr>
        <tr :key="index" class="detail-row">
           <td>{{item.detail}}</td>
        </tr>
      </template>
    </tbody>
  </table>

Answer 3

If you want to use in double tag. Or want to use a separate component in the template div within the table tr tags (as in a new component) you could use style="display: contents" in the first div to keep the table rows inline with each other.

Vue component

<table> 
<template v-for="v-for="(price, index) in prices">
<div :key="price.id"  style="display: contents">
<tr><td>{{price.id}}</td><td>{{price.name}}</td></tr>
<tr col-span="2">{{price.desc}}</tr>
</div>
</template>
</table>

Or if you want to use a separate component for the rows

Table.vue

<template>
<div>
<table class="table">
<thead>
<tr>
<th>Firstname</th>
<th>Lastname</th>
</tr>
</thead>
<tbody>
<template v-for="item in items">
<my-component :item=“item”/>
</template>
</tbody>
</table>
</div>
</template>

my-component.vue

<template>
<div style="display: contents">
<tr>
<td>{{item.firstname}}</td>
<td>{{item.lastname}}</td>
</tr>
<tr>
<td colspan="2" >
{{item.description}}
</td>
</tr>
</div>
</template>