git clone https://xxxxx.git

yarn global add serve
serve study-react

npx terser -c -m -o lib/like_button.min.js -- js/like_button.js

yarn add --dev babel-cli@6 babel-preset-react-app@3
#yarn add --dev @babel/core @babel/cli
#yarn add --dev babel-preset-react-app

mkdir lib

npx babel src/like_button4.js --out-file lib/like_button4.js --presets react-app/prod

npx babel --watch src --out-dir lib --presets react-app/prod