webpack 4 has shipped!
ts-loader
The ts-loader 4 is available too.  For details see our release here.  To start using ts-loader 4:
- When using yarn:yarn add ts-loader@4.1.0 -D
- When using npm:npm install ts-loader@4.1.0 -D
Remember to use this in concert with the webpack 4. To see a working example take a look at the "vanilla" example.
fork-ts-checker-webpack-plugin
There's more! You may like to use the fork-ts-checker-webpack-plugin,
 (aka the ts-loader turbo-booster).  The webpack compatible version has been released to npm as 0.4.1:
- When using yarn:yarn add fork-ts-checker-webpack-plugin@0.4.1 -D
- When using npm:npm install fork-ts-checker-webpack-plugin@0.4.1 -D
To see a working example take a look at the "fork-ts-checker" example.