apolo-vue.vue

<template>
       <item v-for='item in hn.topStories' :key='item.id' :item='item'>
      </item>
</template>

<style>
// ... 
</style>

<script>
function callback_fn (that) {
  console.log(that)
}

export default {
  name: 'item-list',

  props: {
    type: String
  },
  data () {
    return {
      hn: []
    }
  },
  apollo: {
    hn: {
      query: callback_fn(this)
      }
  }
}
</script>