'moment' is not defined export default vue

<template>
  <div>
    <p>{{ formattedDate }}</p>
  </div>
</template>

<script>
  import moment from 'moment';

  export default {
    computed: {
      formattedDate() {
        return moment(this.givenDate).format('YYYY');
      }
    },
    //
  }
</script>