tfs-demos

Node.js / Express Challenge

Part 1 - project setup

Build an Express API that reads from and writes to an existing database

Task 1 - initialise the project

Requirements

• Create a new Node project with npm init -y
• Use ES modules by setting "type": "module" in package.json
• Add scripts

  {
    "scripts": {
      "start": "node server.js",
      "dev": "nodemon server.js",
      "lint": "eslint ."
    }
  }
  

• Install the minimum you need to run an API
  • express
  • A database client that matches your database (for example pg or mysql2)
  • dotenv for environment variables
  • cors if a browser client will call the API
  • nodemon as a dev dependency

Create a sensible repository with package.json, .gitignore, and a basic folder structure such as

  src/
    server.js
    routes/
    controllers/
    db/
    middleware/
    utils/

---

Part 2 - environment configuration

Task 2 - .env and configuration

Requirements

• Create a .env file with at least

  PORT=4000
  DATABASE_URL=postgres://user:pass@localhost:5432/dbname
  

• Load variables with dotenv at app start
• Do not commit real secrets. Provide .env.example with dummy values

Acceptance

• App boots using PORT from the environment
• Database connection string is read from DATABASE_URL

---

Part 3 - first endpoint and app middleware

Task 3 - add an app endpoint

Requirements

• Add GET /test (or similar) that returns
  • 200 OK
  • JSON with {"lorem": "ipsum"} or similar
  • Request this endpoint in a browser just to check that the API is working

Task 4 - baseline middleware

Requirements

• express.json() to parse JSON bodies
• CORS configured so you can call the API from a browser app
• A catch-all 404 handler for unknown routes

Acceptance

• Unknown routes return a JSON 404 with a clear message

---

Part 4 - database access

Task 5 - connection and simple query

Requirements

• Connect to the database from Node.js
• Prove connectivity with a simple query such as SELECT * from [table name]

Acceptance

• Server logs a clear message on successful connection
• Server fails if the database is unreachable

---

Part 5 - implement the API

Use your Database and API design (from those challenges)

Task 6 - read endpoints

Requirements

• Implement list and get by id endpoints for at least one resource in your schema

Task 7 - write endpoints

Requirements

• Implement create and update for the same resource
• On create return 201 Created
• Use PATCH for partial updates, PUT only if replacing the full record
• Implement delete if the design includes it and return 204 No Content on success

---

Stretch goals

• With the GET endpoints, support basic filtering and sorting using query parameters if the design calls for it
• Add pagination using page and per_page or the agreed alternative
• Validate path parameters, query parameters, and request bodies
• On validation failure return 422 Unprocessable Entity with field level errors
• Use 404 Not Found when a record is missing
• Add an error handling middleware at the end of the stack that converts thrown errors and rejected promises into a JSON response with an appropriate status code
• Ensure unhandled errors do not crash the process