Nuxt asyncData result is undefined if using global mixin head() method - vue.js

Question

I'm would like to get titles for my pages dynamically in Nuxt.js in one place.
For that I've created a plugin, which creates global mixin which requests title from server for every page. I'm using asyncData for that and put the response into storage, because SSR is important here.
To show the title on the page I'm using Nuxt head() method and store getter, but it always returns undefined.
If I place this getter on every page it works well, but I would like to define it only once in the plugin.
Is that a Nuxt bug or I'm doing something wrong?
Here's the plugin I wrote:
import Vue from 'vue'
import { mapGetters } from "vuex";
Vue.mixin({
async asyncData({ context, route, store, error }) {
const meta = await store.dispatch('pageMeta/setMetaFromServer', { path: route.path })
return {
pageMetaTitle: meta
}
},
...mapGetters('pageMeta', ['getTitle']),
head() {
return {
title: this.getTitle, // undefined
// title: this.pageMetaTitle - still undefined
};
},
})
I would like to set title in plugin correctly, now it's undefined
Update:
Kinda solved it by using getter and head() in global layout:
computed: {
...mapGetters('pageMeta', ['getTitle']),
}
head() {
return {
title: this.getTitle,
};
},
But still is there an option to use it only in the plugin?
Update 2
Here's the code of setMetaFromServer action
import SeoPagesConnector from '../../connectors/seoPages/v1/seoPagesConnector';
const routesMeta = [
{
path: '/private/kredity',
dynamic: true,
data: {
title: 'TEST 1',
}
},
{
path: '/private/kreditnye-karty',
dynamic: false,
data: {
title: 'TEST'
}
}
];
const initialState = () => ({
title: 'Юником 24',
description: '',
h1: '',
h2: '',
h3: '',
h4: '',
h5: '',
h6: '',
content: '',
meta_robots_content: '',
og_description: '',
og_image: '',
og_title: '',
url: '',
url_canonical: '',
});
export default {
state: initialState,
namespaced: true,
getters: {
getTitle: state => state.title,
getDescription: state => state.description,
getH1: state => state.h1,
},
mutations: {
SET_META_FIELDS(state, { data }) {
if (data) {
Object.entries(data).forEach(([key, value]) => {
state[key] = value;
})
}
},
},
actions: {
async setMetaFromServer(info, { path }) {
const routeMeta = routesMeta.find(route => route.path === path);
let dynamicMeta;
if (routeMeta) {
if (!routeMeta.dynamic) {
info.commit('SET_META_FIELDS', routeMeta);
} else {
try {
dynamicMeta = await new SeoPagesConnector(this.$axios).getSeoPage({ path })
info.commit('SET_META_FIELDS', dynamicMeta);
return dynamicMeta && dynamicMeta.data;
} catch (e) {
info.commit('SET_META_FIELDS', routeMeta);
return routeMeta && routeMeta.data;
}
}
} else {
info.commit('SET_META_FIELDS', { data: initialState() });
return { data: initialState() };
}
return false;
},
}
}