Angular 2 production bundle file is too large
<p>i use webpack bundle my angular 2 project, when i bundle the main file. the file is too large, the file size is about 8M. then whenever i refresh my page, there will be a long time for the browser to load and execute the javascript files. 
I think there may be too many files that i don't needs,but how can i find it and kick it out of my bundle files? 
thank u for give me some advice or some help.</p>

<p>here is my main part of webpack config:
webpack.common.js:</p>

<pre><code>const webpack = require('webpack');
const helpers = require('./helpers');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const ForkCheckerPlugin = require('awesome-typescript-loader').ForkCheckerPlugin;

module.exports = {
    baseUrl: './',
    entry: {
        // 'polyfills': './src/polyfills.ts',
        // 'vendor': './src/vendor.ts',
        'main': './src/main.ts'
    },
    resolve: {
        extensions: ['', '.ts', '.js', '.json'],
        root: helpers.root('src'),
        modulesDirectories: ['node_modules'],
    },
    module: {
        loaders: [
            {
                test: /\.ts$/,
                loaders: ['awesome-typescript-loader', 'angular2-template-loader'],
                exclude: [/\.(spec|e2e)\.ts$/]
            },
            {
                test: /\.json$/,
                loader: 'json-loader'
            },
            {
                test: /\.css$/,
                loaders: ['raw-loader']
            },
            {
                test: /\.html$/,
                loader: 'raw-loader',
                exclude: [helpers.root('src/index.html')]
            },
            {
                test: /\.scss$/,
                loaders: ['raw-loader', 'sass-loader'] // sass-loader not scss-loader
            },
            {
                test: /\.(jpg|png|gif)$/,
                loader: 'file'
            },
            {
                test: /.(png|woff(2)?|eot|ttf|svg)$/,
                loader: 'url-loader'
            }
        ]

    },
    plugins: [
        new ForkCheckerPlugin(),
        // new CopyWebpackPlugin([
        //     {from: 'src/assets', to: 'assets'},
        //     {from: 'src/app/i18n', to: 'app/i18n'},
        //     {from: 'src/loading.css', to: 'loading.css'},
        //     {from: 'src/fonts', to: 'fonts'},
        //     {from: 'src/favicon.ico', to: ''},
        //     {from: 'src/img', to: 'img'}]),
        new HtmlWebpackPlugin({
            template: 'src/index.html',
            chunksSortMode: 'dependency'
        })
    ],

    node: {
        global: 'window',
        crypto: 'empty',
        process: true,
        module: false,
        clearImmediate: false,
        setImmediate: false
    }

};
</code></pre>

<p>webpack.prod.js</p>

<pre><code>const helpers = require('./helpers');
const webpackMerge = require('webpack-merge'); // used to merge webpack configs
const commonConfig = require('./webpack.common.js'); // the settings that are common to prod and dev
/**
 * Webpack Plugins
 */
const webpack = require('webpack');
const ProvidePlugin = require('webpack/lib/ProvidePlugin');
const DefinePlugin = require('webpack/lib/DefinePlugin');
const NormalModuleReplacementPlugin = require('webpack/lib/NormalModuleReplacementPlugin');
const IgnorePlugin = require('webpack/lib/IgnorePlugin');
const DedupePlugin = require('webpack/lib/optimize/DedupePlugin');
const UglifyJsPlugin = require('webpack/lib/optimize/UglifyJsPlugin');
const ForkCheckerPlugin = require('awesome-typescript-loader').ForkCheckerPlugin;
const ENV = process.env.NODE_ENV = process.env.ENV = 'production';
const HOST = process.env.HOST || 'localhost';

module.exports = webpackMerge(commonConfig, {
    devtool: 'source-map',

    output: {
        path: helpers.root('dist'),
        filename: '[name].bundle.js',
        chunkFilename: '[id].chunk.js'
    },

    plugins: [
        // new webpack.NoErrorsPlugin(), // 如果出现任何错误 就终止构建
        // new DedupePlugin(), // 检测完全相同(以及几乎完全相同)的文件 并把它们从输出中移除
        // new webpack.optimize.CommonsChunkPlugin({
        //     name: ['polyfills', 'vendor', 'main'].reverse()
        // }),
        new UglifyJsPlugin({
            beautify: false,
            mangle: { screw_ie8 : true, keep_fnames: true },
            compress: { screw_ie8: true, warnings: false },
            comments: false
        }),
        // new ExtractTextPlugin('[name].[hash].css'), // 把内嵌的 css 抽取成玩不文件 并为其文件名添加 hash 后缀 使得浏览端缓存失效
        new DefinePlugin({ // 定义环境变量
            'process.env': {
                ENV: JSON.stringify(ENV)
            }
        }),
    ],

    htmlLoader: {
        minimize: true,
        removeAttributeQuotes: false,
        caseSensitive: true,
        customAttrSurround: [
            [/#/, /(?:)/],
            [/\*/, /(?:)/],
            [/\[?\(?/, /(?:)/]
        ],
        customAttrAssign: [/\)?\]?=/]
    },

    tslint: {
        emitErrors: true,
        failOnHint: true,
        resourcePath: 'src'
    },

    node: {
        global: 'window',
        crypto: 'empty',
        process: false,
        module: false,
        clearImmediate: false,
        setImmediate: false
    }

});
</code></pre>

<p>i dropped my vendor.ts file
here is my polyfills.ts</p>

<pre><code>// This file includes polyfills needed by Angular 2 and is loaded before
// the app. You can add your own extra polyfills to this file.
// Added parts of es6 which are necessary for your project or your browser support requirements.
import 'core-js/es6/symbol';
import 'core-js/es6/object';
import 'core-js/es6/function';
import 'core-js/es6/parse-int';
import 'core-js/es6/parse-float';
import 'core-js/es6/number';
import 'core-js/es6/math';
import 'core-js/es6/string';
import 'core-js/es6/date';
import 'core-js/es6/array';
import 'core-js/es6/regexp';
import 'core-js/es6/map';
import 'core-js/es6/set';
import 'core-js/es6/reflect';
import 'core-js/es6/weak-map';
import 'core-js/es6/weak-set';

import 'core-js/es7/reflect';
import 'zone.js/dist/zone';
</code></pre>