Как работать с txt файлом как с массивом?

let db = `#31~Страна~ 
@135~Город1~ 
$8~Тип1 
$1~Тип2 
@136~Город2~ 
$8~Тип1 
$15~Тип3`; 
let countries = {}; 
let cities = {}; 
let types = {}; 
 
db.split("\n").reduce((p, s) => { 
  let [, num, name] = s.match(/(\d+)~([^~]+)/); 
   
  switch (s.trim().charAt(0)) { 
    case '#': 
      p.co = num; 
      countries[num] = name; 
      break; 
    case '@': 
      p.ci = num; 
      if (!(p.co in cities)) cities[p.co] = []; 
      cities[p.co].push([p.ci, name]); 
      break; 
    case '$': 
      p.ty = num; 
      if (!(p.ci in types)) types[p.ci] = []; 
      types[p.ci].push([p.ty, name]); 
      break; 
  } 
   
  return p; 
}, {co: null, ci: null, ty: null}); 
 
V = new Vue({ 
  el: '#root', 
  data: { 
    country: -1, 
    city: -1, 
    type: -1 
  } 
});

[v-cloak] { 
  display: none; 
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.16/vue.min.js"></script> 
<div id='root' v-cloak> 
  <select v-model="country"> 
    <option disabled value="-1">Pick your option here</option> 
    <option v-for="(name, key) in countries" :key="key" :value="key">{{ name }}</option> 
  </select> 
  <select v-model="city" v-if="country in cities"> 
    <option disabled value="-1">Pick your option here</option> 
    <option v-for="(city, key) in cities[country]" :key="city[0]" :value="city[0]">{{ city[1] }}</option> 
  </select> 
  <select v-model="type" v-if="city in types"> 
    <option disabled value="-1">Pick your option here</option> 
    <option v-for="(type, key) in types[city]" :key="type[0]" :value="type[0]">{{ type[1] }}</option> 
  </select> 
</div>