I'm having problems with Webpack 4 on a Linux machine. The build works fine in dev mode, but fail in production. It also seems to be working on a windows machine. I did try do downgrade webpack to an older version and nothing.
Nodejs: v10.2.1
*TypeError: Cannot read property 'length' of undefined* at node_modules/uglifyjs-webpack-plugin/dist/uglify/index.js:59
this.workers = workers === true ? _os2.default.cpus().length - 1 : Math.min(Number(workers) || 0, _os2.default.cpus().length - 1);
packge.json
{
"name": "webpack-demo",
"version": "1.0.0",
"license": "MIT",
"scripts": {
"build": "webpack -p"
},
"devDependencies": {},
"dependencies": {
"@types/node": "^10.5.1",
"css-loader": "^0.28.11",
"global": "^4.3.2",
"node-sass": "^4.9.1",
"npm": "^6.1.0",
"sass-loader": "^7.0.3",
"style-loader": "^0.21.0",
"ts-loader": "^4.4.2",
"typescript": "^2.9.2",
"uglifyjs-webpack-plugin": "1.0.0-beta.2",
"webpack": "^4.15.1",
"webpack-cli": "^3.0.8"
}
}
webpack.config.js
const path = require('path');
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
var webpack = require('webpack');
module.exports = {
entry: './src/index.ts',
devtool: 'source-map',
mode: 'production',
module: {
rules: [{
test: /\.tsx?$/,
use: 'ts-loader',
exclude: /node_modules/
},
{
test: /\.scss$/,
use: ['style-loader', 'css-loader', 'sass-loader'],
exclude: /node_modules/
}
],
},
resolve: {
extensions: ['.tsx', '.ts', '.js','.css','.scss']
},
plugins: [
new UglifyJsPlugin()
],
output: {
path: path.resolve(__dirname, 'dist'),
filename: 'main.js'
}
}
Setting mode
to production
in Webpack v4 should do enough optimisations, so there's no need to specifically require the Uglify plugin. Try remove uglifyjs-webpack-plugin
and there's also no need for passing the -p
flag for the build
script.
If you want to customise the Uglify plugin, you can also do so in Webpack's optimization
config, see https://webpack.js.org/configuration/optimization/
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
module.exports = {
//...
optimization: {
minimizer: [
new UglifyJsPlugin({ /* your config */ })
]
}
};
Finally, I have a basic webpack v4 starter boilerplate with all the latest ecosystem on Github, take a look and see if it will help you or not