CODE EXAMPLE FOR PHP

install bootstrap in laravel without ui

npm install bootstrap
npm install sass
npm install sass-loader

Second, create (if not created) resources/sass/app.scss and add this:

@import '~bootstrap';

Third, add compilation in webpack.mix.js:

mix.sass('resources/sass/app.scss', 'public/css')

Than, compile it with by run :

npm run dev

<link href="{{ asset('css/app.css') }}" rel="stylesheet">