laravel 6 use one package repository into another package code example

Example 1: package.json laravel best

mix.styles([
    'public/css/vendor/normalize.css',
    'public/css/vendor/videojs.css'
], 'public/css/all.css');

Example 2: package.json laravel best

mix.sass('resources/assets/sass/app.scss', 'public/css')
   .options({
        postCss: [
            require('postcss-css-variables')()
        ]
   });