It is a sample application using Apollo Federation and React Apollo that illustrates the query batching and deduplication behavior of Apollo Federation. The frontend application is using apollo-link-batch-http. The services implement dataloader to illustrate how gateway will not be able to take advantage of the batch functions for the initial queries. To see how gateway batches subsequent request uncomment frontend/src/components/ListItem.js:13.
Assuming node and npm are installed on your machine and this repository has been cloned.
cd server; npm install; npm run dev
# new tab
cd frontend; & npm install; & npm start