@blacksonic any idea why tree shaking doesn't work if the class extends `React.Component`? Here's a simple reproduction: https://github.com/cdeutsch/typescript-webpack-tree-shaking/commit/cc37b70629de1698f20c0d2cf3af78ccbf18abde#diff-f2a33497e4348acebe5f8fe829ffc6ffR19 Is it a bug with Babel-Minify? Or are there side effects with extending `React.Component`? As you can see `V10` shows up in the prod bundle...  Also note, I upgraded your sample to use: - awesome-typescript-loader@3.2.3 - babel-core@6.26.0 - babel-minify-webpack-plugin@0.2.0 - webpack@3.6.0