Webpack v2 Tree Shaking and UglifyJS Dead Code Elimination Analysis

index.js

import { render } from './script1';

render();

output.bundle.js

/** webpack stuff... **/
([ /* 0 */
/***/
function(e, r, n) {
    "use strict";
    function _classCallCheck(e, r) {
        if (!(e instanceof r)) throw new TypeError("Cannot call a class as a function");
    }
    Object.defineProperty(r, "__esModule", {
        value: !0
    });
    var _ = function() {
        function defineProperties(e, r) {
            for (var n = 0; n < r.length; n++) {
                var _ = r[n];
                _.enumerable = _.enumerable || !1, _.configurable = !0, "value" in _ && (_.writable = !0), 
                Object.defineProperty(e, _.key, _);
            }
        }
        return function(e, r, n) {
            return r && defineProperties(e.prototype, r), n && defineProperties(e, n), e;
        };
    }(), t = function() {
        function Script1() {
            _classCallCheck(this, Script1);
        }
        return _(Script1, null, [ {
            key: "render",
            value: function() {
                console.log("render called");
            }
        }, {
            key: "init",
            value: function() {
                console.log("init called");
            }
        } ]), Script1;
    }();
    r.render = t.render;
}, /* 1 */
/***/
function(e, r, n) {
    "use strict";
    var _ = n(0);
    (0, _.render)();
} ]);

script1.js

class Script1 {

  static render() {
    console.log('render called');
  }

  static init() {
    console.log('init called');
  }
}

export const render = Script1.render;

webpack.config.js

const webpack = require('webpack');
const path = require('path');
const HTMLWebpackPlugin = require('html-webpack-plugin');

module.exports = {
  entry: path.resolve(__dirname, 'src/index.js'),
  output: {
    filename: 'index.bundle.js',
    path: path.resolve(__dirname, 'build')
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: [
          {
            loader: 'babel-loader',
            options: {
              presets: [
                ["es2015", { "modules": false }]
              ]
            }
          }
        ]
      }
    ]
  },
  plugins: [
    new HTMLWebpackPlugin(),
    new webpack.optimize.UglifyJsPlugin({
      beautify: true,
      mangle: {
       screw_ie8: true,
       keep_fnames: true
      },
      compress: {
       screw_ie8: true,
       dead_code: true,
       unused: true
     },
     comments: true
   })
  ]
};

@johnstew oh, actually I have another case, and it's working now. But I assume that init function is not removed because Webpack is able to remove only unused local variables and unused imports. It can't remove unsued class methods.