Vue.locale is not a function - Issue after upgrading to 3.0

I’m getting Unknown TypeError: Vue.locale is not a function

var VueI18n = require('vue-i18n')

Vue.use(VueI18n)
Vue.config.lang = 'sv'
var locales = require('./lang/locales')

Object.keys(locales).forEach(function (lang) {
  Vue.locale(lang, locales[lang])
})

And in my locales file I have like I had in 2.*:

module.exports = {
  en: {
    message: 'Hi',
  },
  sv: {
    message: 'Hej',
  }
}

[alexcroox]

Can confirm, npm install vue-i18n is installing "^6.0.0-alpha.2" which is triggering the error

Uncaught TypeError: __WEBPACK_IMPORTED_MODULE_0_vue___default.a.locale is not a function when following the getting started guide exactly (setting up before initiating vue-router etc)

The error goes away if I manually force in package.json "vue-i18n": "^5.0.3"

[peterthomashorn]

I have the same issue (vue-i18n@^4.0.1) but I do not use vue-router. It is just Vue.js and a custom component. This is my script:

import Vue  from 'vue';
import Search from './search.vue';
import VueI18n from 'vue-i18n';

$(document).foundation();

var locales = {
    de: {
        labels: {
            fairs: "Messen"
        }
    },
    en: {
        labels: {
            fairs: "Fairs"
        }
    }
};

Vue.use(VueI18n);

var documentLanguage = $('html').attr('lang');

Vue.config.lang = documentLanguage;

Object.keys(locales).forEach(function (lang) {
    Vue.locale(lang, locales[lang]);
});

The line setting the locale strings (Vue.locale(lang, locales[lang]);) results in the error _coboo-4a6b9317b0.js:11410 Uncaught TypeError: vue2.default.locale is not a function. Browserify compiles it to:

var _vue = require('vue');
var _vue2 = _interopRequireDefault(_vue);
var _search = require('./search.vue');
var _search2 = _interopRequireDefault(_search);
var _vueI18n = require('vue-i18n');
var _vueI18n2 = _interopRequireDefault(_vueI18n);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

$(document).foundation();

var locales = {
    de: {
        labels: {
            fairs: "Messen"
        }
    },
    en: {
        labels: {
            fairs: "Fairs"
        }
    }
};

_vue2.default.use(_vueI18n2.default);
var documentLanguage = $('html').attr('lang');
_vue2.default.config.lang = documentLanguage;

Object.keys(locales).forEach(function (lang) {
    _vue2.default.locale(lang, locales[lang]);
});