Very simple SASS based Project

package.json

{
  "scripts": {
    "build": "npm run sass:dev && npm run postcss:build",
    "dev": "npm run sass:dev && npm run postcss:dev",
    "watch": "onchange \"assets/scss/**/*.scss\" -- npm run dev",
    "sass:dev": "sass assets/scss/custom.scss assets/css/custom.css",
    "postcss:dev": "postcss assets/css/custom.css --use=autoprefixer --output=assets/css/custom.css",
    "postcss:build": "postcss assets/css/custom.css --use=autoprefixer --use cssnano --output=assets/css/custom.css"
  },
  "browserslist": [
    "last 3 version",
    "> 1%",
    "ie 8",
    "ie 9"
  ],
  "devDependencies": {
    "autoprefixer": "^10.4.8",
    "cssnano": "^5.1.13",
    "onchange": "^7.1.0",
    "postcss-cli": "^10.0.0",
    "sass": "^1.54.5"
  }
}