Webpack.mix.js plugin not used ?

Hi everybody, i work on a project that is using webpack plugins. The problem is that I have the impression that these plugins are not recognized when I build the project. I have no error, and writing anything does not happen (you can see for the second plugin that I have to pass an array of routes, and nothing is evaluated).

Someone has an idea ?

I'm using node 6.9.3, laravel 5.3.