JSFiddle - React, Tailwind, and code Playground

HTML

<div id="vue">
  <select v-model="one">
    <option v-for="n in 10" :value="n">{{n}}</option>
  </select>
  <select v-model="two">
    <option v-for="n in 10" :value="n">{{n}}</option>
  </select>
  <select v-model="three">
    <option v-for="n in 10" :value="n">{{n}}</option>
  </select>
  {{array}}
</div>

JavaScript

new Vue({
  el: '#vue',
  data(){
  	return {
    	one:undefined,
      two:undefined,
      three:undefined
    }
  },
  computed:{
  	array(){
    	let xxx = []
      if(this.one !== undefined) xxx.push(this.one)
      if(this.two !== undefined) xxx.push(this.two)
      if(this.thee !== undefined) xxx.push(this.three)
      return xxx
    }
  }
})