[vue-i18n] Cannot translate the value of keypath...

vue & vue-i18n version

ex: 2.0.0-beta.3, 4.1.0

Steps to reproduce

// main.js

import Vue          from 'vue'
import VueResource  from 'vue-resource'
import VueI18n      from 'vue-i18n'
import router       from './router/routes.js'
import App          from './App'

// =======================
// Store
// =======================
Vue.use(VueResource)

// =======================
// Localization
// =======================
Vue.use(VueI18n)

// let self = this
const lang = 'de'

Vue.locale(lang, function () {
  // self.loading = true
  return fetch('../static/lang_' + lang + '.json', {
    method: 'get',
    headers: {
      'Accept': 'application/json',
      'Content-Type': 'application/json'
    }
  }).then(function (res) {
    return res.json()
  }).then(function (json) {
    // self.loading = false
    if (Object.keys(json).length === 0) {
      return Promise.reject(new Error('locale empty !!'))
    } else {
      return Promise.resolve(json)
    }
  }).catch(function (error) {
    // self.error = error.message
    console.error(error.message)
    return Promise.reject()
  })
}, function () {
  Vue.config.lang = lang
})

/* eslint-disable no-new */
new Vue({
  router,
  render: h => h(App),
  http: {
    root: '/root',
    headers: {
      Authorization: 'Basic YXBpOnBhc3N3b3Jk'
    }
  }
}).$mount('app')

//lang_de.json

{
  "apptitle": "App erstellen",
  "headnav": {
    "help": "Hilfe / FAQ",
    "register": "Registrieren",
    "login": "Anmelden"
  }
}

// Template
<template lang="pug">
  header.brandbar
      h1.brand__title {{ $t("apptitle") }}
</template>

What is Expected?

No warnings 😃

What is actually happening?

I try to use your plugin with webpack and vue, and it does what it says - apptitle is rendered as App erstellen, but i get annoying console-warnings:

[vue-i18n] Cannot translate the value of keypath "apptitle". Use the value of keypath as default

[kazupon]

Hmm. I think that we can resolve with using callback of Vue.locale and v-cloak. e.g. http://jsfiddle.net/kazupon/Lh980stL/8/

[Frozire]

Yeah - just a bit problematic when you have a lot of other dependencies that further delays when you can instantiate vue app instance.

I would much prefer if we could set a variable like “hasLoadedTranslations” on the instance and only then will translations be set.