Компоненты Vue js

<div id="app">
    <my-counter v-for="c in 20"></my-counter>
</div>

<script>
Vue.component('my-counter', {
    template: `
        <div style="border: 1px solid black;padding: 10px">
            <h2>Counter: {{ counter }}</h2>
            <button @click="add">Add to counter</button>
        </div>
    `,
    data: function() {
      return {
        counter: 0
      }
    },
    methods: {
      add: function() {
        this.counter++
      }
    }
  })
 
  new Vue({
    el: '#app'
  })
</script>