// in mixin.js
export default {
  methods: {
    getName: function () {
       return this.$store.getters['myStore/getName'];
    }
  }
}

// im myComponent.vue
<template>
    <h1>{this.getName()}</h1>
<template>
<script>
  import myMixin from './mixin.js
  export default {
    mixins: [myMixin]
  }
</script>