TypeScript + Webpack + Babel + Jest + Sass 構成で生 JS でのカウンターアプリ
npm start
npm run build
npm test
npm install
npm init -y
npm install --save-dev webpack webpack-cli webpack-merge clean-webpack-plugin html-webpack-plugin terser-webpack-plugin webpack-dev-server
npm install --save-dev typescript ts-loader
npx tsc --init
npm install --save-dev babel-loader @babel/core @babel/preset-env @babel/preset-typescript
npm install --save-dev eslint eslint-webpack-plugin @typescript-eslint/eslint-plugin @typescript-eslint/parser
npm install --save-dev jest jsdom eslint-plugin-jest @types/jest @types/jsdom
npm install --save-dev ts-node ts-jest
npx jest --init
npm install --save-dev sass-loader node-sass css-loader mini-css-extract-plugin
npm install --save-dev postcss-loader autoprefixer
npm install --save-dev cssnano