react-in-typescript

Rewrite React and ReactDOM in Typescript.

This project was bootstrapped with Create React App.

Extra Setup

• Uninstall react-dom because I will use my own implementation. I tried to uninstall react, but I added it back because I decided to use react types for API requirements. For example, I simply reuse the types of React.ReactElement, React.ReactNode, React.JSX.IntrinsicElements, rather than define my own versions. This allows me to focus on the core implementation and also guarantees that my code is compatible with react.
• In this project, we need to transform JSX into JS and replace the default React.createElement with MyReact.createElement. Here I use babel-plugin-transform-react-jsx. To customize babel beyond the default config of create-react-app, I found a workaround here.
  • First yarn eject.
  • Then edit config/webpack.config.js by adding the plugin into the the following section (around line 390).

{
    test: /\.(js|mjs|jsx|ts|tsx)$/,
    include: paths.appSrc,
    loader: require.resolve('babel-loader'),
    options: {
    customize: require.resolve(
        'babel-preset-react-app/webpack-overrides'
    ),

    plugins: [
        [
        require.resolve('babel-plugin-named-asset-import'),
        {
            loaderMap: {
            svg: {
                ReactComponent:
                '@svgr/webpack?-svgo,+titleProp,+ref![path]',
            },
            },
        },
        ],
        [ // Add plugin here
        "transform-react-jsx",
        {
            "pragma": "MyReact.createElement" // default pragma is React.createElement
        }
        ],
        isEnvDevelopment &&
        shouldUseReactRefresh &&
        require.resolve('react-refresh/babel'),
    ].filter(Boolean),

• Similarly, in the testing, we also need to transform JSX with JS and use MyReact.createElement. Since this project is using jest with babel-jest, I was inspired by this issue, and created my own transformer for babel-jest. The code is put under config/jest/jsxTransform.js. Then, inside package.json, replace the babel-jest transform as below:

  "jest": {
      ...
      "transform": {
          // "^.+\\.(js|jsx|mjs|cjs|ts|tsx)$": "<rootDir>/node_modules/babel-jest",
          "^.+\\.(js|jsx|ts|tsx)$": "<rootDir>/config/jest/jsxTransform.js",
          ...
      }
      ...
  }

• The webpage does not reload on file change in Windows Linux. I checked this StackOverflow and this Reddit Create React App live reload not working on Ubuntu-18.04, none was working. Then I updated the injectClient from false to true in config/webpackDevServer.config.js. Now auto-reload is working. When I checked the compiled code, I noticed that 0.chunk.js has added about 6000 lines of code of WebsocketClient.js, compared to the old version when the injectClient is false.

Available Scripts

In the project directory, you can run:

yarn start

Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.

The page will reload if you make edits.
You will also see any lint errors in the console.

yarn test

Launches the test runner in the interactive watch mode.
See the section about running tests for more information.

yarn build

Builds the app for production to the build folder.
It correctly bundles React in production mode and optimizes the build for the best performance.

The build is minified and the filenames include the hashes.
Your app is ready to be deployed!

See the section about deployment for more information.