Set default value to option select menu

I want to bind a custom attribute to an option select menu. The <option> tag would simply have an attribute of selected="selected"

<template>
  <div>
    <select>
      <option v-for="" v-bind:selected="[condition ? selected : notSelected]" value="">{{ resource.xprm_name }}</option>
    </select>
  </div>
</template>

data: {
  selected: "selected",
  notSelected: ""
}

This does not work, but if I change v-bind:selected to v-bind:class then it receives the appropriate class, so the logic is working, but not with the selected attribute.

Any way to make it work with such custom attributes?

You can just use v-model for selecting a default value on a select box:

Markup:

<div id="app">
  <select v-model="selected">
     <option value="foo">foo</option>
     <option value="bar">Bar</option>
     <option value="baz">Baz</option>
  </select>
</div>

View Model:

new Vue({
  el: "#app",
  data: {
    selected: 'bar'
  }
});

Here's the JSFiddle: https://jsfiddle.net/Lxfxyqmf/

html:

<div id="myComponent">
    <select v-model="selectedValue">
        <option v-for="listValue in valuesList" :value="listValue">
            {{listValue}}
        </option>
    </select>
    <span>Chosen item: {{ selectedValue }}</span>
</div>

js:

var app = new Vue({
    el: '#myComponent',
    data: {
        selectedValue: 'Two',
        valuesList: ['One', 'Two', 'Three']
    },

I have created a reusable component of select that also emits the modelValue to parent component.

If you look at the first option tag, you can see how I create a default value using props.

BaseSelect.vue (child component)

<template>
  <label v-if="label">{{ label }}</label>
  <select
    class="field"
    :value="modelValue"
    v-bind="{
      ...$attrs,
      onChange: ($event) => {
        $emit('update:modelValue', $event.target.value);
      },
    }"
  >
    <option value="" disabled>{{ defaultValue }}</option>
    <option
      v-for="option in options"
      :key="option"
      :value="option"
      :selected="option === modelValue"
    >
      {{ option }}
    </option>
  </select>
</template>

<script>
export default {
  props: {
    label: {
      type: String,
      default: ""
    },
    defaultValue: {
      type: String,
      default: "Select an item of the list",
      required: false
    },
    modelValue: {
      type: [String, Number],
      default: "Otros"
    },
    options: {
      type: Array,
      required: true
    },
  },
};
</script>

Parent component

<BaseSelect
      label="Asunto"
      defaultValue = "Selecciona un asunto" 
      v-model="contactValues.asunto"
      :options="asuntos"
    />

Notice that you have to receipt correctly this value in your data() (v-model)

Using the new composition API:

<template>
     <select v-model="selectValue">
         <option value="a">
             Option a
         </option>
         <option value="b">
             Option b
         </option>
      </select>
</template>

<script>
import { ref } from 'vue';

export default {
    setup() {
        // Create a reactive value for our select
        const selectValue = ref('a');

        // Return to the template
        return { selectValue };
    },
};
</script>