GraphQL API Server (NestJS)

Backend Engineer Code Test — GraphQL API Server built with NestJS (TypeScript) and Apollo Server.

Tech Stack

• Language: Node.js (>= 16) + TypeScript
• Framework: NestJS 11
• GraphQL: @nestjs/graphql 13 + Apollo Driver (@apollo/server 5)
• Config: @nestjs/config (.env)

Features

• Implements the provided GraphQL schema (Action, Trigger, Response, ResourceTemplate, NodeObject) in schema-first mode
• Uses the provided JSON files (action.json, trigger.json, response.json, node.json, resourceTemplate.json) as the data source
• Resolves cross-references between entities:
  • NodeObject.trigger / triggerId
  • NodeObject.responses / responseIds
  • NodeObject.actions / actionIds (mapped from postActions in the raw data)
  • NodeObject.parents / parentIds (mapped from composite IDs)
  • Action.resourceTemplate / Trigger.resourceTemplate
• Authenticated via Bearer token (HTTP 401 UNAUTHENTICATED when missing/invalid)
  • Express middleware rejects invalid requests at the HTTP layer
  • Global AuthGuard provides GraphQL-layer defense in depth
• Custom Long and JSON scalars

Getting Started

npm install
npm run start:dev        # watch mode
# or
npm run build && npm start

Server will run at http://localhost:4000/graphql.

GraphQL Playground / Apollo Studio Sandbox requires the Authorization header. Use a tool like Postman, or the Apollo Studio Sandbox with the header Authorization: Bearer <token>.

Authentication

Send the following header with every request:

Authorization: Bearer code-test-token-2026

The token is configurable via the AUTH_TOKEN environment variable (see .env).

Example Query

query {
  node(nodeId: "6297172e70a0c165b989cd10") {
    _id
    name
    parentIds
    parents {
      _id
      name
      compositeId
    }
    trigger {
      _id
      name
      resourceTemplate {
        _id
        name
        key
      }
    }
    responses {
      _id
      name
      platforms {
        integrationId
        build
        localeGroups {
          localeGroupId
          variations {
            name
            responses
          }
        }
      }
    }
    actions {
      _id
      name
      resourceTemplate {
        _id
        name
      }
    }
  }
}

cURL Example

curl -X POST http://localhost:4000/graphql \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer code-test-token-2026" \
  -d '{"query":"{ node(nodeId: \"6296be3470a0c1052f89cccb\") { _id name } }"}'

Project Structure

graphql-api-nest/
├── data/                        # JSON data source files
│   ├── action.json
│   ├── node.json
│   ├── resourceTemplate.json
│   ├── response.json
│   └── trigger.json
├── src/
│   ├── main.ts                  # Bootstrap + Bearer token middleware
│   ├── app.module.ts            # GraphQLModule (ApolloDriver) + ConfigModule + global AuthGuard
│   ├── common/
│   │   └── auth/
│   │       └── auth.guard.ts    # GraphQL-aware global guard (401 UNAUTHENTICATED)
│   ├── data/
│   │   ├── data.module.ts       # @Global data module
│   │   ├── data.service.ts      # JSON loading + _id/compositeId indexing
│   │   └── types.ts             # Entity interfaces
│   └── graphql/
│       ├── typeDefs.ts          # Provided GraphQL schema (SDL)
│       ├── scalars/
│       │   ├── long.scalar.ts   # Long custom scalar
│       │   └── json.scalar.ts   # JSON custom scalar
│       └── node/
│           ├── node.resolver.ts         # @Resolver('NodeObject') query + field resolvers
│           └── related.resolvers.ts     # Action/Trigger/Response/ResourceTemplate resolvers
├── .env                         # AUTH_TOKEN and PORT configuration
├── .gitignore
├── nest-cli.json
├── tsconfig.json
└── package.json

Data Mapping Notes

The raw JSON files use slightly different field names than the provided schema. The resolvers map them as follows:

Schema field	Source field(s)
NodeObject.triggerId / trigger	trigger (ID)
NodeObject.responseIds / responses	responses (array of IDs)
NodeObject.actionIds / actions	postActions (array of IDs)
NodeObject.parentIds / parents	parents (array of composite IDs, resolved via compositeId)
ResponseLocaleGroup.localeGroupId	localeGroup
ResourceTemplate.createdAt	falls back to 0 when missing