Frontend med npm scripts, Sass, PostCSS, Rollup, Babel, Autoprefixer et al

.babelrc

{
  "presets": ["@babel/preset-env"]
}

.browserslistrc

last 2 version
> 2% in NO
not ie <= 11
Firefox ESR

package.json

{
  "name": "mitt-prosjekt",
  "version": "1.0.0",
  "description": "Eksempelprosjekt",
  "main": "index.js",
  "scripts": {
    "clean": "rimraf ./dist",
    "build:sass": "node-sass ./src/css/master.scss ./dist/assets/style.css",
    "build:autoprefixer": "postcss ./dist/assets/style.css --output ./dist/assets/style.min.css --map",
    "build:css": "npm run build:sass && npm run build:autoprefixer",
    "build:rollup": "rollup -c",
    "build:uglify": "uglifyjs ./dist/assets/app.js --compress --mangle --source-map --output ./dist/assets/app.min.js",
    "build:js": "npm run build:rollup && npm run build:uglify",
    "build": "npm run build:css && npm run build:js",
    "build:prod": "npm run clean && npm run build",
    "watch:css": " watch 'npm run build:css' ./src/css",
    "watch:js": " watch 'npm run build:js' ./src/js",
    "watch": "npm run watch:css & npm run watch:js",
    "serve": "http-server ./dist -p 8080 --cors",
    "dev": "npm run serve & npm run watch"
  },
  "author": "NullSprite",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.2.2",
    "@babel/preset-env": "^7.2.3",
    "autoprefixer": "^9.4.5",
    "copy": "^0.3.2",
    "cssnano": "^4.1.8",
    "http-server": "^0.11.1",
    "node-sass": "^4.11.0",
    "postcss": "^7.0.11",
    "postcss-cli": "^6.1.1",
    "rimraf": "^2.6.3",
    "rollup": "^1.1.0",
    "rollup-plugin-babel": "^4.3.0",
    "rollup-plugin-node-resolve": "^4.0.0",
    "uglify-js": "^3.4.9",
    "watch": "^1.0.2"
  },
  "dependencies": {}
}

postcss.config.js

module.exports = {
  plugins: [
    require('autoprefixer')({grid: true}),
    require('cssnano')
  ]
};

rollup.config.js

import resolve from 'rollup-plugin-node-resolve';
import babel from 'rollup-plugin-babel';

export default {
  input: 'src/js/index.js',
  output: {
    name: 'my-app',
    file: 'dist/assets/app.js',
    format: 'cjs'
  },
  plugins: [
    resolve(),
    babel({
      exclude: 'node_modules/**'
    })
  ]
};