Razzle TypeScript Example

How to use

Create and start the example:

npx create-razzle-app --example with-typescript-plugin with-typescript-plugin

cd with-typescript-plugin
yarn start

Idea behind the example

This is an of how to use Razzle with TypeScript. In razzle.config.js, we locate the part of the webpack configuration that is running babel-loader and swap it out for ts-loader. Additionally, we make sure Razzle knows how to resolve .ts and .tsx files.

Lastly, we also need to modify our Jest configuration to handle typescript files. Thus we add ts-jest and @types/jest to our dev dependencies. Then we augment Razzle's default jest setup by adding a field in our package.json.

// package.json

{
  ...
  "jest": {
    "transform": {
      "\\.(ts|tsx)$": "<rootDir>/node_modules/ts-jest/preprocessor.js",
      "\\.css$": "<rootDir>/node_modules/razzle/config/jest/cssTransform.js",
      "^(?!.*\\.(js|jsx|css|json)$)": "<rootDir>/node_modules/razzle/config/jest/fileTransform.js"
    },
    "testMatch": [
      "<rootDir>/src/**/__tests__/**/*.(ts|js)?(x)",
      "<rootDir>/src/**/?(*.)(spec|test).(ts|js)?(x)"
    ],
    "moduleFileExtensions": [
      "ts",
      "tsx",
      "js",
      "json"
    ],
    "collectCoverageFrom": [
      "src/**/*.{js,jsx,ts,tsx}"
    ]
  }
}

The tslint.json and tsconfig.json are taken from Microsoft's official TypeScript-React-Starter.

Note: You do not techincally need to fully replace babel-loader with ts-loader to use TypeScript. Both TS and Babel transpile ES6 code, so when you run both webpack loaders you are making Razzle do twice the work. From our testing, this can make HMR extremely slow on larger apps. Thus, this example overwrites babel-loader with ts-loader. However, if you are incrementally moving to typescript you may want to run both loaders side by side. If you are running both, add this to your jest.transform setup in package.json:

"^.+\\.(js|jsx)$": "<rootDir>/node_modules/razzle/config/jest/babelTransform.js",

This will continue to transform .js files through babel.