[npm]

npm.php

// you install js package with npm this command install one version of library to folder node_modules
// then type : npm run dev : this command check file resurse/sass/app.sass and get all require name library and add all js code to file publie/js/app.js
// now you can use lib to your project

// for example when you install and then add @import '~bootstrap/scss/bootstrap'; it added to your project

//***** if you look at file package.json in bootstrap folder in node/moudols you can see (jquery) this mean that jquery is installed in your project with bootstrap - if you want to use it you should add <scrip src:"{{asset('js/app.js')}}"></script>
// in file welcome.blade.php app.js not added but in file layout/app.blade.php it is.