react 国际化了解一下

背景

楼主最近新接了一个项目，从0开始做，需要做多语言的国际化，今天搞了一下，基本达到了想要的效果， 在这里简单分享下：

---

一些探索

也说不上是探索吧，就Google了一波， GitHub 上找了一个比较成熟的库 react-i18next， 写了一些代码，现将过程分享一下， 附带详细代码，手把手教你实现国际化。

先睹为快

先看一下最后的成果：

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

// xxx component
console.log('i18n来一发:', i18n.t('INVALID_ORDER'));

render() { 
  // ...
  <button> {i18n.t('INVALID_ORDER')} </button>
}

控制台中：

对应json 中的信息：

开始

原理

原理其实很简单： 字符串替换。

拉取远程的国际化json文件到本地，再根据语言做一个映射就可以了。

废话不多说， 来看代码吧。

先简单看一下目录结构：

先看一下 config 里面的 相关代码：

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, <img src={process.env.PUBLIC_URL + '/img/logo.png'} />.
        // 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 相关的代码就好了， 其他的都create-react-app 的相关配置， 不用管。

再看下 language.js 里面的逻辑：

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;

逻辑也比较简单， 根据语言列表把对应的json 内容加进来。 作为示例，这里我设置的是 英文 和 印尼语。

下面看 i18n 文件里面的内容：

locales 里面放的是语言的json 文件， 内容大概是：

{
    "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 ${locale} keys...\n${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}\n`)
    console.log(`${operation}\t${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;
}

这些准备工作做好后, 还需要把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(
  <I18nextProvider i18n={i18n}>
    <Provider store={configureStore(rootReducer)} >
      <Router history={history}>
        <App />
      </Router>
    </Provider>
  </I18nextProvider>,
  ROOT
);

如何使用

加入上面的代码后， 控制台会有一些log 信息， 表示语言已经加载好了。

在具体的业务组件中，使用方法是：

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

console.log('哈哈哈哈哈i18n来一发:', i18n.t('INVALID_ORDER'));

控制台中：

对应json 中的信息：

后面你就可以愉快的加各种词条了。

Tips

我们在src 中的文件中引入了src 目录外的文件， 这是create-react-app 做的限制， 编译会报错， 把它去掉就好了：

---

关于多语言的设置

代码示例：

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

初始化的时候可以设置默认语言， 如需要切换系统语言， 可以调用 i18n 提供的方法：

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

// ...

  // 设置为印尼语
  changeLanguage('id');

为了保存语言设置, 可以把 language 保存在 localStorage 中, 使用的时候直接从 storage 里取。

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结语

这里作为例， 就是把语言的json 文件下载下来放到locales 目录里， 如果想实时拉取，要保证文件下载完之后再render app.

类似：

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

当然你也可以免了这一步，直接下载好放到工程里来。

大概就是这样，以上就是实现国际化的全部代码，希望对大家有所帮助。