Special HelloWorld.vue component

This is a first version of a rough around the edges Vue.js component. I built it as fast as possible. I just used lodash as a dependency.

<template>
  <div class="selector">
    <button @click="onClickButton" class="main">{{getTotal}} selected</button>

    <div v-if="selectorOpen">
      <button @click="selectAll">All</button>
      <button @click="selectNone">None</button>

      <ul>
        <li v-for="item in countries" @click="onClickList(item.country)">
          <input type="checkbox" checked v-if="item.checked">
          <input type="checkbox" v-else>
          {{item.country}}
        </li>
      </ul>
    </div>

    <div class="hello">
      Hello, {{getCountryListString}}!
    </div>
  </div>
</template>

<script>
import {map, size, filter} from 'lodash'

export default {
  name: 'HelloWorld',
  data () {
    return {
      countries: [
          { country: 'Russia', checked: true },
          { country: 'US', checked: false },
          { country: 'China', checked: false },
          { country: 'Europe', checked: false },
          { country: 'India', checked: false },
          { country: 'Japan', checked: false }
      ],
      selectorOpen: false
    }
  },
  computed: {
    getChecked () {
      return filter(this.countries, (item, idx) => {
        return item.checked === true
      })
    },
    getTotal () {
      return size(this.getChecked)
    },
    getCountryListString () {
      const names = map(this.getChecked, (i) => {
        return i.country
      })
      return size(names) > 0 ? names.join(', ') : 'everybody'
    }
  },
  methods: {
    onClickButton () {
      this.selectorOpen = !this.selectorOpen
    },
    onClickList (country) {
      this.countries = map(this.countries, (i, idx) => {
        if (i.country === country) {
          return {...i, checked: !i.checked}
        }

        return i
      })
    },
    selectAll () {
      this.countries = map(this.countries, (i, idx) => {
        return {...i, checked: true}
      })
    },
    selectNone () {
      this.countries = map(this.countries, (i, idx) => {
        return {...i, checked: false}
      })
    }
  }
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
.selector {
  width: 400px;
  margin: 20px auto;
  padding: 10px;
}
button.main {
  width: 100%;
  margin-bottom: 2px;
}
ul {
  margin: 10px 0px;
  padding: 0;
  height: 90px;
  overflow: auto;
  text-align: left;
  background-color: #f1f1f1;
  border: 1px solid #ccc;
}
li {
  list-style: none;
}

</style>