How to automatically choose the first option in a v-for loop in Vue.js

Question

How to automatically choose the first option in a v-for loop in Vue.js

I have a loop that creates a dropdown menu from an array:

 <select class="form-control" v-model="compare_version" >
            <option
              v-for="(version, index) in allVersions"
              v-bind:value="index"
              v-bind:key="version.versionid"
              :selected="version.versionid === 0"
            >{{ version.versionid }}</option>
          </select>

My goal is to set the first value of the dropdown as the default.

The options are showing up but the first one is not being selected by default.

Can anyone spot the mistake in my code? Your help would be much appreciated!

javascript vue.js v-for

Answer 1

Answer №1

To set the default value as 0 for compare_version, you can do so within the data() function while binding the index from the iterating list as the captured value in the model. The use of v-model will handle this process efficiently.

Furthermore, it is advisable to remove the :selected binding when keeping in mind that the captured value from the select tag corresponds to the index of the list.

var vm = new Vue({
  el: "#vue-instance",
  data: {
    compare_version: 0,
    allVersions: [
      {versionId: 'A'},
      {versionId: 'B'},
      {versionId: 'C'}
    ]
  }
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
 <!DOCTYPE html>
<html>
<body>
<div id="vue-instance">
<select v-model="compare_version">
    <option v-for="(x,index) in allVersions"
            v-bind:value="index"
            v-bind:key="x.text">{{x.versionId}}</option>
  </select>
  <span>Selected: {{ compare_version }}</span>
</div>
</body>
</html>

Answer 2

To set the default value as 0 for compare_version, you can do so within the data() function while binding the index from the iterating list as the captured value in the model. The use of v-model will handle this process efficiently.

Furthermore, it is advisable to remove the :selected binding when keeping in mind that the captured value from the select tag corresponds to the index of the list.

var vm = new Vue({
  el: "#vue-instance",
  data: {
    compare_version: 0,
    allVersions: [
      {versionId: 'A'},
      {versionId: 'B'},
      {versionId: 'C'}
    ]
  }
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
 <!DOCTYPE html>
<html>
<body>
<div id="vue-instance">
<select v-model="compare_version">
    <option v-for="(x,index) in allVersions"
            v-bind:value="index"
            v-bind:key="x.text">{{x.versionId}}</option>
  </select>
  <span>Selected: {{ compare_version }}</span>
</div>
</body>
</html>

How to automatically choose the first option in a v-for loop in Vue.js

Answer №1

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