Fallback localization

The following locale messages that not exist message key in ja locale:

const messages = {
  en: {
    message: 'hello world'
  ja: {

When specify the fallbackLocale option to VueI18n constructor option, message key is localized with en locale key:

const i18n = new VueI18n({
  locale: 'ja',
  fallbackLocale: 'en',

Template the below:

<p>{{ $t('message') }}</p>

Output the below:

<p>hello world</p>
Last Updated: 5/30/2018, 5:08:26 PM