如何从vue脚本中的函数返回值？

Question

我使用Vue框架，我有一个.vue文件，我希望在其中获取当前创建的Country（）。我的代码如下：

 <template>
    <div id="show-blogs">
        <h1>All Blog Articles</h1>
        <input type="text" v-model="search" placeholder="search blogs" />
        <!-- INPUT -->
        <input type="text" v-model="message" required id="selectedCountry"/>
        <!-- BUTTON ADD BLOG -->
        <button v-on:click="selectCountry">Select country</button>

        <div v-for="blog in filteredBlogs" class="single-blog">
            <!-- router-link = href -->
            <router-link v-bind:to="'/blog/' + blog.id">
                <h2>{{ blog.country }}</h2>
            </router-link>
            <p>{{ blog.city }}</p>
            <p>{{ blog.category }}</p>
            <p>{{ blog.phoneNumber }}</p>

        </div>
    </div>
</template>

<script>        
    var currentCountry = getCurrentCountry();        

    import searchMixin from '../mixins/searchMixin';

    export default {        

        data() {


            return {
                blogs: [],
                search: '',

            }
        },    


        methods: {
            selectCountry: function() {
                selectedCountry = document.getElementById("selectedCountry").value;
                this.$http.get('https://aggelies-7fde2.firebaseio.com/posts/' + selectedCountry + '.json').then(function(data) {

                    return data.json()
                }).then(function(data) {
                    var blogsArray = [];
                    for (let key in data) {
                        data[key].id = key;
                        blogsArray.push(data[key]);
                    }
                    this.blogs = blogsArray;

                });

            },


            getCurrentCountry: function() {
                var currCountry;

                var requestUrl = "http://ip-api.com/json";

                $.ajax({
                    url: requestUrl,
                    type: 'GET',
                    async: false,
                    success: function(json) {

                        currCountry = json.country.toUpperCase();

                    },
                    error: function(err) {

                    }
                });

                alert(currCountry);
                return currCountry;

            }

        },


        created() {

            this.$http.get('https://aggelies-7fde2.firebaseio.com/posts/' + currentCountry + '.json').then(function(data) {

                return data.json()
            }).then(function(data) {
                var blogsArray = [];
                for (let key in data) {
                    data[key].id = key;
                    blogsArray.push(data[key]);
                }
                this.blogs = blogsArray;
                //console.log(this.blogs);
            });
        },


        mixins: [searchMixin]
    }
</script>

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

ajax代码工作正常，我得到了当前的国家/地区。但是当我在脚本getCurrentCountry（）的开头调用时，该函数不起作用，我没有得到返回值，以便将它分配给currentCountry。有什么建议是错的吗？