This project was bootstrapped with TSDX.
Run yarn build to build the project and then node dist/index.js to run the server. The server starts on port 5050. Use your favourite REST client to make a request to localhost:5050. The handler will then use a mock list of rates that contain standardCodeId and fetch each one on their own iteration. But using dataloader all those fetches will be batched and only a single request will be made.