Webpack-2 recursive tree-shaking/dead code elimination.

Hello, i’ve been trying out webpack@2.0.7-beta and noticed that webpack doesn’t eliminate dead code recursively. Let me show you an example:

import { otherFunc1, otherFunc2 } from './otherModule';

function callOther() {
  otherFunc1();
  otherFunc2();
}

export default function () {
  if (process.env.NODE_ENV !== 'production') {
    callOther();
  }
}

Let’s say process.env.NODE_ENV === 'production', so the condition is always false.

1. I would expect the whole if block in default function to be stripped out.
2. So callOther would get stripped out.
3. So otherFunc1 and otherFunc2 would get stripped out(they aren’t used anywhere else).

Webpack does steps 1 and 2, but skips step 3, so otherFunc1 and otherFunc2 end up in the bundle anyway.

If i call otherFunc1 and otherFunc2 directly inside the if block, they don’t end up in the bundle.

My webpack.config.js:

'use strict';

var webpack = require('webpack');

var env = process.env.NODE_ENV;

var config = {
  module: {
    loaders: [
      { test: /\.js$/, loader: 'babel-loader', exclude: /node_modules/ }
    ]
  },
  output: {
    library: 'bundle',
    libraryTarget: 'umd'
  },
  plugins: [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify(env)
    })
  ]
};

module.exports = config;

My .babelrc:

{
  "plugins": [
    ["transform-es2015-template-literals", { "loose": true }],
      "transform-es2015-arrow-functions",
      "transform-es2015-shorthand-properties",
      ["transform-es2015-computed-properties", { "loose": true }],
      "check-es2015-constants",
      ["transform-es2015-spread", { "loose": true }],
      "transform-es2015-parameters",
      ["transform-es2015-destructuring", { "loose": true }],
      "transform-es2015-block-scoping",
      "transform-object-rest-spread",
  ]
}

And i call webpack with:

cross-env NODE_ENV=production webpack -p src/index.js dist/bundle.min.js"

Thanks!