optionsComponent.vue

// ...
<script>
import { fetchUserPosts } from '@/api'

export default {
    props: {
        id: Number
    },
    data() {
        return {
            isLoading: true,
            pageOffset: 0,
            posts: []
        }
    },
    watch: {
        id: {
            handler: 'fetchPosts',
            immediate: true
        }
    },
    mounted() {
        window.addEventListener('scroll', this.update)
    },
    destroyed() {
        window.removeEventListener('scroll', this.update)
    },
    methods: {
        async fetchPosts() {
            this.isLoading = true
            this.posts = await fetchUserPosts(this.id)
            this.isLoading = false
        },
        update() {
            this.pageOffset = window.pageYOffset
        }
    },
    computed: {
        count() {
            return this.posts.length
        }
    }
}
</script>
// ...