feat: add zero-config support for fork-ts-checker-webpack-plugin

[piotr-oles]

Hi! 👋
I'm a maintainer of the fork-ts-checker-webpack-plugin.
Currently, we have to set transpileOnly: true to skip type-checking on the loader side.
With this change it's no longer the case - the loader will detect if there is a checker plugin in the configuration and set default transpileOnly: true if that's the case. I hope this will improve DX and make webpack config files cleaner and smarter :)

Before:

// webpack.config.js
const ForkTsCheckerWebpackPlugin = require('fork-ts-checker-webpack-plugin');

module.exports = {
  context: __dirname, // to automatically find tsconfig.json
  entry: './src/index.ts',
  resolve: {
    extensions: [".ts", ".tsx", ".js"],
  },
  module: {
    rules: [
      {
        test: /\.tsx?$/,
        loader: 'ts-loader',
        options: {
          // disable type checker - we will use it in fork plugin
          transpileOnly: true
        }
      }
    ]
  },
  plugins: [new ForkTsCheckerWebpackPlugin()]
};

After:

// webpack.config.js
const ForkTsCheckerWebpackPlugin = require('fork-ts-checker-webpack-plugin');

module.exports = {
  context: __dirname, // to automatically find tsconfig.json
  entry: './src/index.ts',
  resolve: {
    extensions: [".ts", ".tsx", ".js"],
  },
  module: {
    rules: [
      {
        test: /\.tsx?$/,
        loader: 'ts-loader'
      }
    ]
  },
  plugins: [new ForkTsCheckerWebpackPlugin()]
};

I tested this manually, please let me know if you need some automatic tests for this.

[johnnyreilly]

Hey @piotr-oles - I know who you are! 😅

I think this is a great improvement! Could we make an enhancement? With the current implementation, you can't explicitly control transpileOnly - it's always derived from whether the plugin is present.

If someone wants to run with transpileOnly and not use a checker, we'd still want to support that.

So passing transpileOnly: false should be possible in the absence of checker usage. Would you be up for making that change?

[johnnyreilly]

Actually, I read that wrong - your PR already implements the behaviour I mentioned. Could you update the README.md to document new usage of fork-ts-checker-webpack-plugin, increment the version in the package.json and add an entry to the CHANGELOG.md please?

[piotr-oles]

Sure, I will do that!

[piotr-oles]

Done! ✅

[johnnyreilly]

Let's ship it!

[johnnyreilly]

https://github.com/TypeStrong/ts-loader/releases/tag/v9.3.0 - https://github.com/TypeStrong/ts-loader/actions/runs/2249111694