SOURCE

new Vue({
  el: '#app',
  data: {
    numbers: [ 1, 2, 3, 4, 5 ],
    window: window,
    counter: 1,
  },
  computed: {
    evenNumbers: function () {
      return this.numbers.filter(function (number) {
        return number % 2 === 0
      })
    },
    ou () {
      return this.numbers.filter((item) => {
        return item%2 == 0;
      })
    }
  },
  methods: {
    test (e) {
      this.counter++
      alert(event.target.tagName)
    }
  }
})

<div id="app">
  <ul>
    <li v-for="n in ou" v-on:click="test">{{ n }}</li>
    {{ counter }}
  </ul>
</div>