According to laravel mix Install Process .
npm install laravel-mix --save-dev
webpack.mix.js configuration
let mix = require('laravel-mix');
mix.js('assets/src/app.js', './assets/js')
.sass('assets/src/app.scss', './assets/css')
.setPublicPath('./assets');
Details:
1. mix.js(convert js file), mix.sass(convert sass file into css) and mix.setPublicPath( root path ).
2. Javascript and sass file store assets>src folder. We write a code in this files. When we build it than convert two file as below locations. We write a scss code but build it pure css.
a. assets>js (same name as mix file)
b. assets>css (same name as mix file)