How to setup TypeScript + Babel + Webpack?

Question

I have these dependencies:

"devDependencies": {
  "@types/node": "^4.0.27-alpha",
  "babel-core": "^6.10.4",
  "babel-loader": "^6.2.4",
  "babel-polyfill": "^6.9.1",
  "babel-preset-es2015": "^6.9.0",
  "babel-preset-stage-0": "^6.5.0",
  "ts-loader": "^0.8.2",
  "typescript": "^2.0.0",
  "webpack": "^1.13.1"
}

.babelrc:

{
  "presets": [
    "es2015",
    "stage-0"
  ]
}

tsconfig.json:

{
    "compilerOptions": {
        "module": "commonjs",
        "target": "es6",
        "noImplicitAny": false,
        "sourceMap": false,
        "outDir": "built"
    },
    "exclude": [
        "node_modules"
    ]
}

webpack.config.js:

module.exports = {
  entry: ['babel-polyfill', './src/'],
  output: {
    path: __dirname,
    filename: './built/bundle.js',
  },
  resolve: {
    modulesDirectories: ['node_modules'],
    extensions: ['', '.js', '.ts'],
  },
  module: {
    loaders: [{
      test: /\.tsx?$/, loaders: ['ts-loader', 'babel-loader'], exclude: /node_modules/
    }],
  }
};

/src/index.ts:

async function foo() {
  const value = await bar();
  console.log(value);
}

function bar() {
  return new Promise((resolve, reject) => {
    return resolve(4);
  });
}

(async function run() {
  await foo();
}());

With this setup it does work, I can build and run it (logs 4 correctly). However I'm always getting some errors on Webpack:

ERROR in ./src/index.ts
(4,32): error TS2304: Cannot find name 'regeneratorRuntime'.

ERROR in ./src/index.ts
(6,12): error TS2304: Cannot find name 'regeneratorRuntime'.

ERROR in ./src/index.ts
(31,451): error TS2346: Supplied parameters do not match any signature of call target.

ERROR in ./src/index.ts
(40,33): error TS2304: Cannot find name 'regeneratorRuntime'.

ERROR in ./src/index.ts
(41,12): error TS2304: Cannot find name 'regeneratorRuntime'.

It seems it has something to do with babel-polyfill . What am I missing?

Answer 1

Babel 7 does not need ts-loader.

As of Babel 7 the ts-loader is unnecessary, because Babel 7 understands TypeScript . Complete details of a TypeScript + Babel7 + Webpack setup are here .

An overview of the set up without ts-loader.

Install Babel's TypeScript support. Only @babel/preset-typescript is mandatory; the other three add additional features that TypeScript supports.

npm install --save-dev @babel/preset-typescript 
npm install --save-dev @babel/preset-env 
npm install --save-dev @babel/plugin-proposal-class-properties 
npm install --save-dev @babel/plugin-proposal-object-rest-spread

Configure the additional .babelrc plugins and presets.

{
    "presets": [
        "@babel/preset-env",
        "@babel/preset-typescript"
    ],
    "plugins": [
        "@babel/proposal-class-properties",
        "@babel/proposal-object-rest-spread"
    ]
}

And update your webpack.config.js (other code is omitted for clarity).

module: {
  rules: [
  {
     test: /\.(js|jsx|tsx|ts)$/,
     exclude: /node_modules/,
     loader: 'babel-loader'
    }
  ]
},
resolve: {
  extensions: ['*', '.js', '.jsx', '.tsx', '.ts'],
},

Answer 2

Loaders always execute right to left, so changing to

test: /\.tsx?$/, loaders: ['babel-loader', 'ts-loader'], exclude: /node_modules/

fixed the issue since it is going to run ts-loader first.

Full webpack.config.js file:

module.exports = {
  entry: ['babel-polyfill', './src/'],
  output: {
    path: __dirname,
    filename: './dist/index.js',
  },
  resolve: {
    extensions: ['', '.js', '.ts'],
  },
  module: {
    loaders: [{
      test: /\.ts$/, loaders: ['babel-loader', 'ts-loader'], exclude: /node_modules/
    }],
  }
};

Sample project: brunolm/typescript-babel-webpack .

Answer 3

(4,32): error TS2304: Cannot find name 'regeneratorRuntime'.

This is a symptom that the output of babel is getting fed to ts . This order is wrong

Fix

You compilation setup should have TS output fed to Babel.

Alternatively you can compile TypeScript with just Babel using @babel/preset-typescript .

More

Compiling TypeScript with Babel : https://babeljs.io/docs/en/babel-preset-typescript