TypeError - 使用 i18next 時無法讀取未定義的屬性“使用”

Question

我有一個具有以下依賴項的項目：

 "dependencies": {
    "@hapi/joi": "^17.1.1",
    "bcrypt": "^5.0.1",
    "config": "^3.3.7",
    "express": "^4.17.3",
    "express-async-errors": "^3.1.1",
    "express-rest-i18n": "^1.0.1",
    "http-status-codes": "^2.2.0",
    "i18next": "^21.6.14",
    "i18next-http-backend": "^1.4.0",
    "i18next-http-middleware": "^3.2.0",
    "joi": "^17.4.2",
    "lodash": "^4.17.21",
    "mongoose": "^6.2.4",
    "validator": "^13.7.0"
  },

我的 i18n 配置代碼如下：

const i18next = require("i18next").default;
const Backend = require("i18next-http-backend").default;
const i18nextMiddleware = require("i18next-http-middleware");

i18next
  .use(Backend)
  .use(i18nextMiddleware.LanguageDetector)
  .init({
    backend: {
      loadPath: __dirname + `/locales/{{lng}}/{{ns}}.json`,
    },
    fallbackLng: "en",
    preload: ["en"],
  });

module.exports = { i18next };

我的應用程序代碼如下：

const { i18next } = require("../locales/i18n");
const messages = require("../locales/en/translation.json");
const i18nextMiddleware = require("i18next-http-middleware");

require("express-async-errors");
const express = require("express");

const app = express();
app.use(express.json());
app.use(i18nextMiddleware.handle(i18next));

app.get("*", (req, res) => {
  const response = req.t("greeting");
  res.status(200);
  res.send(response);
});

const port = process.env.PORT || 3000;
module.exports = app.listen(port, () =>
  console.log(`Listening on port: ${port}`)
);

當我通過運行 npm start 啟動應用程序時，我收到錯誤： TypeError: Cannot read property 'use' of undefined

存在此錯誤是因為配置文件中的 Backend 未定義。 我使用https://www.npmjs.com/package/i18next-http-middleware作為資源。

為什么我會收到此錯誤，我該如何解決？

Answer 1

你為什么訪問.default？

像這樣導入：

const i18next = require("i18next");
const Backend = require("i18next-http-backend");