Add minimal GraphQL demo service (Apollo Server 4 + Express, in-memory store)

[Copilot]

The repository contained only a LICENSE and a one-line README. This adds a runnable backend service exposing a GraphQL API over a small User/Post domain, with in-memory storage so it works from a clean checkout without external dependencies.

Changes

• Project setup — package.json (Node ESM, @apollo/server 4, express, graphql, cors), lockfile, .gitignore. Scripts: start, dev (node --watch), test.
• Service (src/)
  • index.js — Express bootstrap, /graphql endpoint (port 4000, PORT override) plus a /health probe.
  • server.js — Apollo Server factory, split from the HTTP bootstrap so tests can execute operations without binding a port.
  • schema.js — User, Post; queries users, user(id), posts, post(id); mutations createUser, createPost.
  • resolvers.js — includes nested User.posts / Post.author; createPost rejects unknown authorId with BAD_USER_INPUT since referential integrity isn't enforced by the store.
  • data/store.js — in-memory store with seed data, exposing a database-like API and injected via the GraphQL context, so it can be swapped for a persistent backend without touching resolvers.
• Tests (test/graphql.test.js) — built-in node:test runner, no extra dev dependencies; each test gets a fresh store.
• README — stack, structure, install, run, endpoint URL, example queries/mutations and a curl example.

Example

curl http://localhost:4000/graphql -H 'Content-Type: application/json' \
  -d '{"query":"{ users { id name posts { title } } }"}'

{"data":{"users":[{"id":"1","name":"Ada Lovelace","posts":[{"title":"Hello GraphQL"}]}, ...]}}

Data resets to seed state on every restart, which is intentional for a demo service.

[Copilot]

🟡 Changes recommended

The declared Node.js support range and dependency choices don’t match the current test/runtime requirements (Node engine mismatch; Apollo Server v4 EOL), and the README contains environment-dependent behavior presented as unconditional.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds a minimal Node.js backend service exposing a GraphQL API (User/Post) using Apollo Server on Express, backed by an in-memory store, with tests and documentation to support local development and verification.

Changes:

• Introduces GraphQL schema + resolvers + in-memory store for a small demo domain.
• Adds an Express HTTP bootstrap exposing /graphql and /health.
• Adds node:test-based API tests and a comprehensive README with usage examples.

File summaries

File	Description
test/graphql.test.js	Exercises queries/mutations against the Apollo schema using executeOperation.
src/server.js	Exposes an ApolloServer factory for reuse by HTTP bootstrap and tests.
src/schema.js	Defines the User/Post GraphQL schema and operations.
src/resolvers.js	Implements query/mutation and field resolvers backed by the store.
src/index.js	Boots an Express server, wires Apollo middleware, adds /health.
src/data/store.js	Implements a tiny in-memory “DB-like” store with seed data.
README.md	Documents setup, endpoints, and example operations.
package.json	Defines runtime scripts, engines, and dependencies.
package-lock.json	Locks dependency graph for reproducible installs.
.gitignore	Ignores Node/artifact files (node_modules, coverage, env files).

Review details

• Files reviewed: 8/10 changed files
• Comments generated: 4
• Review effort level: Lite

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[charles2ke]

@copilot Fix the code for this review comment.

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[charles2ke]

@copilot Fix the code for this review comment.

When a review comment includes a suggested change, apply the suggestion exactly.

Do not make changes beyond what is described in the linked review comment.

[charles2ke]

@copilot Fix the code for this review comment.

When a review comment includes a suggested change, apply the suggestion exactly.

Do not make changes beyond what is described in the linked review comment.

[charles2ke]

@copilot Fix the code for this review comment.

When a review comment includes a suggested change, apply the suggestion exactly.

Do not make changes beyond what is described in the linked review comment.

[charles2ke]

@copilot Fix the code for all comments in this review thread.

When a review comment includes a suggested change, apply the suggestion exactly.

Do not make changes beyond what is described in the linked review thread.