After migrating my project from Webpack 3 and Babel 6 to Webpack 4 and Babel 7 then bundle size has increased. The project compiles fine, but the bundle size is now 1MB larger than before. I have been working hard to decrease the bundle size so this behaviour was a little dissapointing. I am apparently missing something. 「(°ヘ°)
My old webpack.config.js (Webpack 3)
const path = require('path')
const webpack = require('webpack')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const UglifyJSPlugin = require('uglifyjs-webpack-plugin')
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
process.env.NODE_ENV = process.env.NODE_ENV || 'development'
if (process.env.NODE_ENV === 'test') {
require('dotenv').config({ path: '.env.test' })
} else if (process.env.NODE_ENV === 'development') {
require('dotenv').config({ path: '.env.development' })
} else if (process.env.NODE_ENV === 'production') {
require('dotenv').config({ path: '.env.production' })
} else {
require('dotenv').config({ path: '.env.development' })
}
module.exports = (env) => {
const isProduction = env === 'production';
const CSSExtract = new ExtractTextPlugin('styles.css');
return {
entry: ['babel-polyfill', './src/app.js'],
output: {
path: path.join(__dirname, 'public', 'dist'), //absolute path
filename: 'bundle.js'
},
module: {
rules: [{
loader: 'babel-loader',
test: /\.js$/,
exclude: [
/node_modules/,
/firebase-functions/
]
}, {
test: /\.s?css$/,
use: CSSExtract.extract({
use: [
{
loader: 'css-loader',
options: {
sourceMap: true
}
}, {
loader: 'sass-loader',
options: {
sourceMap: true
}
}
]
})
}, {
test: /\.(png|jpe?g|gif)$/,
use: [
{
loader: 'file-loader',
options: {},
},
],
}, {
test: /\.svg$/,
use: ['@svgr/webpack'],
}]
},
plugins: [
CSSExtract,
new UglifyJSPlugin(),
new webpack.DefinePlugin({
'process.env.FIREBASE_API_KEY': JSON.stringify(process.env.FIREBASE_API_KEY),
'process.env.FIREBASE_AUTH_DOMAIN': JSON.stringify(process.env.FIREBASE_AUTH_DOMAIN),
'process.env.FIREBASE_DATABASE_URL': JSON.stringify(process.env.FIREBASE_DATABASE_URL),
'process.env.FIREBASE_PROJECT_ID': JSON.stringify(process.env.FIREBASE_PROJECT_ID),
'process.env.FIREBASE_STORAGE_BUCKET': JSON.stringify(process.env.FIREBASE_STORAGE_BUCKET),
'process.env.FIREBASE_MESSAGING_SENDER_ID': JSON.stringify(process.env.FIREBASE_MESSAGING_SENDER_ID),
'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV),
}),
new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
new BundleAnalyzerPlugin(),
],
devtool: isProduction ? 'source-map' : 'inline-source-map',
devServer: {
contentBase: path.join(__dirname, 'public'),
historyApiFallback: true,
publicPath: '/dist'
}
};
}
My new webpack.config.js (Webpack 4)
'use strict'
const path = require('path')
const webpack = require('webpack')
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
const TerserPlugin = require('terser-webpack-plugin')
process.env.NODE_ENV = process.env.NODE_ENV || 'development'
if (process.env.NODE_ENV === 'test') {
require('dotenv').config({ path: '.env.test' })
} else if (process.env.NODE_ENV === 'development') {
require('dotenv').config({ path: '.env.development' })
} else if (process.env.NODE_ENV === 'production') {
require('dotenv').config({ path: '.env.production' })
} else {
require('dotenv').config({ path: '.env.development' })
}
module.exports = (env) => {
const isDev = env === 'development'
const bundleName = 'bundle.js'
const firebasePlugin = new webpack.DefinePlugin({
'process.env.FIREBASE_API_KEY': JSON.stringify(process.env.FIREBASE_API_KEY),
'process.env.FIREBASE_AUTH_DOMAIN': JSON.stringify(process.env.FIREBASE_AUTH_DOMAIN),
'process.env.FIREBASE_DATABASE_URL': JSON.stringify(process.env.FIREBASE_DATABASE_URL),
'process.env.FIREBASE_PROJECT_ID': JSON.stringify(process.env.FIREBASE_PROJECT_ID),
'process.env.FIREBASE_STORAGE_BUCKET': JSON.stringify(process.env.FIREBASE_STORAGE_BUCKET),
'process.env.FIREBASE_MESSAGING_SENDER_ID': JSON.stringify(process.env.FIREBASE_MESSAGING_SENDER_ID),
'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV),
})
const plugins = isDev ?
[
firebasePlugin,
new BundleAnalyzerPlugin()
]
:
[
firebasePlugin,
new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
]
// build WEBPACK CONFIG
const config = {}
config.devServer = {
contentBase: path.join(__dirname, 'public'), //absolute path
historyApiFallback: true,
publicPath: '/dist'
}
config.mode = env
config.watch = isDev
config.resolve = {
extensions: ['.js', '.jsx']
}
config.devtool = 'source-map'
config.entry = ['@babel/polyfill', './src/app.js']
config.output = {
path: path.join(__dirname, 'public', 'dist'), //absolute path
filename: bundleName
}
config.optimization = {
minimizer: [
new TerserPlugin({
sourceMap: isDev,
cache: true,
parallel: true,
terserOptions: {
mangle: false,
keep_classnames: true,
keep_fnames: true,
output: {
comments: false
}
}
})
]
}
config.plugins = plugins;
config.module = {
rules: [
{
test: /\.(js|jsx)$/,
exclude: [
/node_modules/,
/firebase-functions/
],
use: {
loader: 'babel-loader'
}
},
{
test: /\.svg$/,
loader: 'svg-inline-loader'
},
{
test: /\.css$/i,
use: ['style-loader', 'css-loader'],
},
{
test: /\.s[ac]ss$/i,
use: [
'style-loader',
'css-loader',
'sass-loader',
],
}
]
}
return config
}
With Webpack 3 my bundle size was 2.6M. It now weights in at 3.6M. :/ Have I missed something? How can I optimise Webpack to reduce bundle size?
Many thanks! K
I think there is something with your images (maybe all of the images inlined to your js?). Where is your file-loader configuration for webpack4? How do you load it now?
I can help more if you will share resulting bundle for wp3 and wp4.
There are optimizations i can see:
1) set terserOptions.mangle to true. it will not rename your properties (because mangle.properties is disabled until you don't set mangle property to { properties: true }), bundle will work i think. and other terser options can be reduced
2) babel/polyfill is a huge thing, you don't need it's full version. also, it was deprecated in favor of core-js@3.
babel now have a nice feature useBuiltIns: usage which will include only polyfills you need to the bundle.