摘要：先睹為快先看一下最后的成果來一發(fā)控制臺中對應中的信息開始原理原理其實很簡單字符串替換。拉取遠程的國際化文件到本地，再根據(jù)語言做一個映射就可以了。

樓主最近新接了一個項目，從0開始做，需要做多語言的國際化，今天搞了一下，基本達到了想要的效果， 在這里簡單分享下：

也說不上是探索吧，就Google了一波， GitHub 上找了一個比較成熟的庫 react-i18next， 寫了一些代碼，現(xiàn)將過程分享一下， 附帶詳細代碼，手把手教你實現(xiàn)國際化。

先看一下最后的成果：

 // ...
import i18n from "@src/i18n";

// xxx component
console.log("i18n來一發(fā):", i18n.t("INVALID_ORDER"));

render() { 
  // ...
   {i18n.t("INVALID_ORDER")} 
}

控制臺中：

對應json 中的信息：

原理其實很簡單： 字符串替換。

拉取遠程的國際化json文件到本地，再根據(jù)語言做一個映射就可以了。

廢話不多說， 來看代碼吧。

先簡單看一下目錄結構：

先看一下 config 里面的 相關代碼：

env.js:

"use strict";

const fs = require("fs");
const path = require("path");
const paths = require("./paths");
const languages = require("./languages");

// Make sure that including paths.js after env.js will read .env variables.
delete require.cache[require.resolve("./paths")];

const NODE_ENV = process.env.NODE_ENV;
if (!NODE_ENV) {
  throw new Error(
    "The NODE_ENV environment variable is required but was not specified."
  );
}

// https://github.com/bkeepers/dotenv#what-other-env-files-can-i-use
var dotenvFiles = [
  `${paths.dotenv}.${NODE_ENV}.local`,
  `${paths.dotenv}.${NODE_ENV}`,
  // Don"t include `.env.local` for `test` environment
  // since normally you expect tests to produce the same
  // results for everyone
  NODE_ENV !== "test" && `${paths.dotenv}.local`,
  paths.dotenv,
].filter(Boolean);

// Load environment variables from .env* files. Suppress warnings using silent
// if this file is missing. dotenv will never modify any environment variables
// that have already been set.  Variable expansion is supported in .env files.
// https://github.com/motdotla/dotenv
// https://github.com/motdotla/dotenv-expand
dotenvFiles.forEach(dotenvFile => {
  if (fs.existsSync(dotenvFile)) {
    require("dotenv-expand")(
      require("dotenv").config({
        path: dotenvFile,
      })
    );
  }
});

// We support resolving modules according to `NODE_PATH`.
// This lets you use absolute paths in imports inside large monorepos:
// https://github.com/facebookincubator/create-react-app/issues/253.
// It works similar to `NODE_PATH` in Node itself:
// https://nodejs.org/api/modules.html#modules_loading_from_the_global_folders
// Note that unlike in Node, only *relative* paths from `NODE_PATH` are honored.
// Otherwise, we risk importing Node.js core modules into an app instead of Webpack shims.
// https://github.com/facebookincubator/create-react-app/issues/1023#issuecomment-265344421
// We also resolve them to make sure all tools using them work consistently.
const appDirectory = fs.realpathSync(process.cwd());
process.env.NODE_PATH = (process.env.NODE_PATH || "")
  .split(path.delimiter)
  .filter(folder => folder && !path.isAbsolute(folder))
  .map(folder => path.resolve(appDirectory, folder))
  .join(path.delimiter);

// Grab NODE_ENV and REACT_APP_* environment variables and prepare them to be
// injected into the application via DefinePlugin in Webpack configuration.
const REACT_APP = /^REACT_APP_/i;

function getClientEnvironment(publicUrl) {
  const raw = Object.keys(process.env)
    .filter(key => REACT_APP.test(key))
    .reduce(
      (env, key) => {
        env[key] = process.env[key];
        return env;
      },
      {
        // Useful for determining whether we’re running in production mode.
        // Most importantly, it switches React into the correct mode.
        NODE_ENV: process.env.NODE_ENV || "development",
        // Useful for resolving the correct path to static assets in `public`.
        // For example, .
        // This should only be used as an escape hatch. Normally you would put
        // images into the `src` and `import` them in code to get their paths.
        PUBLIC_URL: publicUrl,
        LANGUAGE: {
          resources: languages.resources,
          defaultLng: languages.defaultLng
        },
        COUNTRY: process.env.COUNTRY
      }
    );
  // Stringify all values so we can feed into Webpack DefinePlugin
  const stringified = {
    "process.env": Object.keys(raw).reduce((env, key) => {
      env[key] = JSON.stringify(raw[key]);
      return env;
    }, {}),
  };

  return { raw, stringified };
}

module.exports = getClientEnvironment;

主要看lannguage 相關的代碼就好了， 其他的都create-react-app 的相關配置， 不用管。

再看下 language.js 里面的邏輯：

const path = require("path");
const paths = require("./paths");
const localesHash = require("../i18n/localesHash");
const resourcesHash = require("../i18n/resourcesHash");

const COUNTRY = process.env.COUNTRY || "sg";
const country = (COUNTRY).toUpperCase();
const defaultLng = localesHash[country][0];

const langs = [
  "en",
  "id"
];

const prefixLangs = [];
const entries = {};

for (let i = 0, len = langs.length; i < len; i++) {
  const prefixLang = `dict_${langs[i]}`
  prefixLangs.push(prefixLang)
  entries[prefixLang] = path.resolve(paths.appSrc, `../i18n/locales/${langs[i]}.json`)
}

const resources = {
  [defaultLng]: {
    common: resourcesHash[defaultLng]
  }
}

exports.resources = resources;
exports.defaultLng = defaultLng;

邏輯也比較簡單， 根據(jù)語言列表把對應的json 內容加進來。 作為示例，這里我設置的是 英文 和 印尼語。

下面看 i18n 文件里面的內容：

locales 里面放的是語言的json 文件， 內容大概是：

{
    "msg_Created": "Pesanan telah terbuat"
    // ...
}

localesHash.js:

module.exports = {
  SG: ["en"],
  ID: ["id"]
}

resourcesHash.js:

module.exports = {
  "en": require("./locales/en.json"),
  "id": require("./locales/id.json")
}

index.js

const path = require("path")
const fs = require("fs")
const fetch = require("isomorphic-fetch")
const localesHash = require("./localesHash")

const argv = process.argv.slice(2)
const country = (argv[0] || "").toUpperCase()

const i18nServerURI = locale => {
  const keywords = {
    "en": "en",
    "id": "id"
  }
  const keyword = keywords[locale]
  return keyword === "en"
    ? "your/transify/website/json/download"
    : `your/transify/website/${keyword}/json/download`
}

const fetchKeys = async (locale) => {
  const uri = i18nServerURI(locale)
  console.log(`Downloading ${locale} keys...
${uri}`)
  const respones = await fetch(uri)
  const keys = await respones.json()
  return keys
}

const access = async (filepath) => {
  return new Promise((resolve, reject) => {
    fs.access(filepath, (err) => {
      if (err) {
        if (err.code === "EXIST") {
          resolve(true)
        }
        resolve(false)
      }
      resolve(true)
    })
  })
}

const run = async () => {
  const locales = localesHash[country] || Object
    .values(localesHash)
    .reduce(
      (previous, current) =>
        previous.concat(current), []
    )
  if (locales === undefined) {
    console.error("This country is not in service.")
    return
  }
  for (const locale of locales) {
    const keys = await fetchKeys(locale)
    const data = JSON.stringify(keys, null, 2)
    const directoryPath = path.resolve(__dirname, "locales")
    if (!fs.existsSync(directoryPath)) {
      fs.mkdirSync(directoryPath)
    }
    const filepath = path.resolve(__dirname, `locales/${locale}.json`)
    const isExist = await access(filepath)
    const operation = isExist ? "update" : "create"
    console.log(operation)
    fs.writeFileSync(filepath, `${data}
`)
    console.log(`${operation}	${filepath}`)
  }
}

run();

再看下src 中的配置：

i18nn.js

import i18next from "i18next"
import { firstLetterUpper } from "./common/helpers/util";
const env = process.env;
let LANGUAGE = process.env.LANGUAGE;
LANGUAGE = typeof LANGUAGE === "string" ? JSON.parse(LANGUAGE) : LANGUAGE

const { defaultLng, resources } = LANGUAGE

i18next
  .init({
    lng: defaultLng,
    fallbackLng: defaultLng,
    defaultNS: "common",
    keySeparator: false,
    debug: env.NODE_ENV === "development",
    resources,
    interpolation: {
      escapeValue: false
    },
    react: {
      wait: false,
      bindI18n: "languageChanged loaded",
      bindStore: "added removed",
      nsMode: "default"
    }
  })

function isMatch(str, substr) {
  return str.indexOf(substr) > -1 || str.toLowerCase().indexOf(substr) > -1
}

export const changeLanguage = (locale) => {
  i18next.changeLanguage(locale)
}

// Uppercase the first letter of every word. abcd => Abcd or abcd efg => Abcd Efg
export const tUpper = (str, allWords = true) => {
  return firstLetterUpper(i18next.t(str), allWords)
}

// Uppercase all letters. abcd => ABCD
export const tUpperCase = (str) => {
  return i18next.t(str).toUpperCase()
}

export const loadResource = lng => {
  let p;

  return new Promise((resolve, reject) => {
    if (isMatch(defaultLng, lng)) resolve()

    switch (lng) {
      case "id":
        p = import("../i18n/locales/id.json")
        break
      default:
        p = import("../i18n/locales/en.json")
    }

    p.then(data => {
      i18next.addResourceBundle(lng, "common", data)
      changeLanguage(lng)
    })
      .then(resolve)
      .catch(reject)
  })
}

export default i18next

 // firstLetterUpper

export const firstLetterUpper = (str, allWords = true) => {
  let tmp = str.replace(/^(.)/g, $1 => $1.toUpperCase())
  if (allWords) {
    tmp = tmp.replace(/s(.)/g, $1 => $1.toUpperCase())
  }
  return tmp;
}

這些準備工作做好后, 還需要把i18n 注入到app中：

index.js:

import React from "react";
import { render } from "react-dom";
import { Provider } from "react-redux";
import rootReducer from "./common/redux/reducers";
import { configureStore } from "./common/redux/store";
import { Router } from "react-router-dom";
import createBrowserHistory from "history/createBrowserHistory";
import { I18nextProvider } from "react-i18next";
import i18n from "./i18n";
import "./common/styles/index.less";
import App from "./App";
export const history = createBrowserHistory();

const ROOT = document.getElementById("root");

render(
  
    
      
        
      
    
  ,
  ROOT
);

加入上面的代碼后， 控制臺會有一些log 信息， 表示語言已經(jīng)加載好了。

在具體的業(yè)務組件中，使用方法是：

 // ...
import i18n from "@src/i18n";

console.log("哈哈哈哈哈i18n來一發(fā):", i18n.t("INVALID_ORDER"));

控制臺中：

對應json 中的信息：

后面你就可以愉快的加各種詞條了。

我們在src 中的文件中引入了src 目錄外的文件， 這是create-react-app 做的限制， 編譯會報錯， 把它去掉就好了：

代碼示例：

i18next.init({
  lng: "en",
});

初始化的時候可以設置默認語言， 如需要切換系統(tǒng)語言， 可以調用 i18n 提供的方法：

import { changeLanguage } from "@src/i18n";

// ...

  // 設置為印尼語
  changeLanguage("id");

為了保存語言設置, 可以把 language 保存在 localStorage 中, 使用的時候直接從 storage 里取。

這里作為例， 就是把語言的json 文件下載下來放到locales 目錄里， 如果想實時拉取，要保證文件下載完之后再render app.

類似：

loadResource(getLocale())
  .then(() => {
    import("./app.js")
  })

當然你也可以免了這一步，直接下載好放到工程里來。

大概就是這樣，以上就是實現(xiàn)國際化的全部代碼，希望對大家有所幫助。