How to include postcss-merge-rules in webpack?

Question

webpack

Greetings!
Tell me, how to correctly connect the postcss-merge-rules library for wepback ? I would like to achieve a similar gluing of classes and css properties for identical elements.
I suppose that this plugin should be connected here, but how exactly should it be connected? Part of code from webpack.config.js:

{
    	loader: 'postcss-loader',
    	options: {
    		ident: 'postcss',
    		sourceMap: !isProduction,
    		plugins: (() => {
    			return isProduction ? [
    				require('autoprefixer')(),
    				require('cssnano')({
    					preset: ['default', {
    						minifySelectors: true
    					}]
    				})
    			] : []
    		})()
    	}
    }

Long googling and sorting through various options for connecting this library did not give any results ...
Thank you!

Answer 1

Did you try to follow the link and see an example of using postcss? Yet it is written.
https://github.com/postcss/postcss#usage
What is not clear about this?