Using NPM compile SASS to css

On your project you have to run npm init -y first, then

npm install node-sass --save

In the package.json, add this 2 lines

{
  "name": "clean",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "sass" : "node-sass scss/main.scss --output css --source-map-embed --source-map-contents --output-style compressed",
    "watch:sass": "npm run sass -- --watch"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

Then save, and run

npm run watch:sass