how to run start:production command from package json code example

Example: npm start for production

{
  "scripts": {
    "start": "NODE_ENV=development REACT_SERVER_CONFIGS=_configs/development/ react-server start",
    "start-beta": "NODE_ENV=beta REACT_SERVER_CONFIGS=_configs/beta/ react-server start",
    "start-prod": "NODE_ENV=production REACT_SERVER_CONFIGS=_configs/production/ react-server start"
  }
}