<script src="https://cdn.staticfile.org/vue/2.2.2/vue.min.js"></script>

<div id="app">

  {{ message,message2 | capitalize('aa') }}

</div>

new Vue({

  el: '#app',

  data: {

    message: 'runoob',

    message2: 'runoob'

  },

  filters: {

    capitalize: function (value,value2,value3) {

      if (!value) return ''

      value = value.toString()

      return value.charAt(0).toUpperCase() + value.slice(1)+value.substring(0,value2.length-1)+value2.charAt(value2.length-1).toUpperCase()+" "+value3

    }

  }

})