I am using webpack 4 and I am unsure if my code is being compressed and minified. I am using React as well.
My first problem is using the Webpack UglifyJS plugin in the webpack plugin
property or the optimization
property. When I use the plugin
property it seems to compress at least but not to a single line. I am still unsure if it is minifying. When I use optimization
it does not even compress. When I take a look at my bundled js file, it seems to be bundling things in node_modules
such as webpack
.
//works with plugin
module.exports = {
...
plugins: [new UglifyJsPlugin({
test: /\.js$/,
exclude: /node_modules/,
sourceMap: true,
uglifyOptions: {
compress: {},
mangle: true,
}
}],
//does not work with optimization
module.exports = {
...
optimization: {
minimize: true,
minimizer: [new UglifyJsPlugin({
test: /\.js$/,
exclude: /node_modules/,
sourceMap: true,
uglifyOptions: {
compress: {},
mangle: true,
}
}],
}
With the first example, the code gets compressed at least but not into one single line.
//Example
!*** ./node_modules/scheduler/index.js ***!
\*****************************************/
/*! no static exports found */function(module,exports,__webpack_require__){"use strict";eval('\n\nif (false) {} else {\n...
!*** ./node_modules/scheduler/tracing.js ***!
\*******************************************/
/*! no static exports found */function(module,exports,__webpack_require__){"use strict";eval('\n\nif (false) {...
Also not sure if it being minified. I wrote a function in my React Component
someFunc(one, two) {
return one + two
}
According to the npm uglifyjs docs, this should be minified into
someFunc(a, b) { \n return a+b\n}
but it is being output as
someFunc(one, two) { \n return one + two\n}
Is this minifying?
In webpack, minification process is controlled through two configuration fields: optimization. minimize flag to toggle it and optimization. minimizer array to configure the process. To tune the defaults, we'll attach terser-webpack-plugin to the project so that it's possible to adjust it.
Webpack v4+ will minify your code by default in production mode .
UglifyJS is a JavaScript compressor/minifier written in JavaScript. It also contains tools that allow one to automate working with JavaScript code: A parser which produces an abstract syntax tree (AST) from JavaScript code.
Minification is just removing unnecesary whitespace and redundant / optional tokens like curlys and semicolons, and can be reversed by using a linter. Uglification is the act of transforming the code into an "unreadable" form, that is, renaming variables/functions to hide the original intent...
Webpack 4 does optimization and minification by default in production
mode.
So if my guess is right, your configuration is development
configuration.
You can remove your explicit UglifyJsPlugin definition and set the mode
to production
and Webpack will take care of everything.
mode: 'production',
plugins: [...],
optimization: ...
You can customize your optimizations though if you must. But setting the mode to production
will yield you your expected results.
More info here
Webpack 4 mode usage
I was also facing the same issue. It started working after providing mode config value as production.
module.exports = {
// webpack config
mode: process.env.NODE_ENV || 'development',
};
// command NODE_ENV=production webpack
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