Webpack动态导入.json文件？

Question

我正在将 React Intl 用于 x 种语言（如下所示），目前我在设置应用程序的位置导入以下内容：

import { addLocaleData } from 'react-intl';
import locale_en from 'react-intl/locale-data/en';
import locale_de from 'react-intl/locale-data/de';

import messages_en from './translations/en.json';
import messages_de from './translations/de.json';

addLocaleData([...locale_en, ...locale_de]);

...
export const messages = {
    en: messages_en,
    de: messages_de
}

由于无论使用哪种语言，这些语言文件都会被导入，我的主捆绑 js 文件变得相当大，尤其是 .json 文件。

如何使用 Webpack 拆分这些语言文件（或使用 CopyWebpackPlugin 将它们复制到我的 dist 文件夹中），然后根据当前使用的语言动态导入它们？

该应用程序是同构的，因此相同的代码正在服务器上运行。

Answer 1

I've been working on something like this lately, although I don't need SSR for my project. I found that pairing dynamic import syntax with React's Suspense component achieves the desired result. Here's a rough overview of what I found to work, at least in my case, which doesn't include SSR:

// wrap this around your JSX in App.js:
<React.Suspense fallback={<SomeLoadingComponent />}>
  <AsyncIntlProvider>
    {/* app child components go here */}
  </AsyncIntlProvider>
</React.Suspense>

// the rest is in support of this
// can be placed in another file
// simply import AsyncIntlProvider in App.js

const messagesCache = {};

const AsyncIntlProvider = ({ children }) => {
  // replace with your app's locale getting logic
  // if based on a hook like useState, should kick off re-render and load new message bundle when locale changes (but I haven't tested this yet)
  const locale = getLocale();

  const messages = getMessages(locale);
  return (
    <IntlProvider locale={locale} messages={messages}>
      {children}
    </IntlProvider>
  );
};

function getMessages(locale) {
  if (messagesCache[locale]) {
    return messagesCache[locale];
  }
  // Suspense is based on ErrorBoundary
  // throwing a promise will cause <SomeLoadingComponent /> to render until the promise resolves
  throw loadMessages(locale);
}

async function loadMessages(locale) {
  // dynamic import syntax tells webpack to split this module into its own chunk
  const messages = await import('./path/to/${locale}.json`);
  messagesCache[locale] = messages;
  return messages;
}

Webpack should split each locale JSON file into its own chunk. If it doesn't, something is likely transpiling the dynamic import syntax to a different module system (require, etc) before it reaches webpack. For example: if using Typescript, tsconfig needs "module": "esnext" to preserve import() syntax. If using Babel, it may try to do module transpilation too.

The chunk output for a single locale will look something like this; definitely more than would be achieved via CopyWebpackPlugin:

(window["webpackJsonp"] = window["webpackJsonp"] || []).push([[0],{

/***/ "./path/to/en-US.json":
/*!*************************************!*\
  !*** ./path/to/en-US.json ***!
  \*************************************/
/*! exports provided: message.id, default */
/***/ (function(module) {

eval("module.exports = JSON.parse(\"{\\\"message.id\\\":\\\"Localized message text\\\"}\");//# sourceURL=[module]\n//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiLi9zcmMvbG9jYWxpemF0aW9uL2VuLVVTLmpzb24uanMiLCJzb3VyY2VzIjpbXSwibWFwcGluZ3MiOiIiLCJzb3VyY2VSb290IjoiIn0=\n//# sourceURL=webpack-internal:///./path/to/en-US.json\n");

/***/ })

}]);

Hopefully, this is a good starting point and either works with SSR or can be modified to work with SSR. Please report back with your findings on that subject.