Reactでnpm startでローカル立ち上げ時のポート番号を指定する方法
package.jsonの、 start": "react-scripts start" に PORT=3001 を追加
"scripts": { "start": "PORT=3001 react-scripts start", "build": "react-scripts build", "test": "react-scripts test", "eject": "react-scripts eject" },
