This guide explains how to run the code examples for each level.

⚠️ Important

Each level's code is self-contained and should be run from its own directory. Do NOT try to run them from the root directory unless you understand the project structure.

🟢 Beginner Level

Location

01-beginner/demo-beginner/

Setup

cd 01-beginner/demo-beginner
npm install

Run

npm run start:dev

Access

  • Backend API: http://localhost:3000
  • Frontend UI: http://localhost:3000/

🟡 Intermediate Level

Location

02-intermediate/code/

Setup

cd 02-intermediate/code
npm install

Run

npm run start:dev

Access

  • Backend API: http://localhost:3000
  • Test with: curl http://localhost:3000/

Authentication

Use any token for testing:

curl http://localhost:3000/users \
  -H "Authorization: Bearer valid-token"

🔴 Advanced Level

Location

03-advanced/code/

Setup

cd 03-advanced/code
npm install

Run

npm run start:dev

Access

  • Backend API: http://localhost:3000

📦 Examples (Complete Working Demo)

Location

examples/backend/ and examples/frontend/

Setup

From project root:

npm install

Run

From project root:

npm run start:dev

This runs the examples backend which serves the frontend.

Access

  • Backend API: http://localhost:3000/api
  • Frontend UI: http://localhost:3000/public/index.html

🔧 Troubleshooting

Error: Module not found

Problem: Dependencies not installed

Solution:

cd [level-directory]
npm install

Error: Cannot find module '@nestjs/common'

Problem: Running from wrong directory or dependencies not installed

Solution: 1. Make sure you're in the correct directory 2. Run npm install in that directory 3. Try again

Error: Port already in use

Problem: Another server is running on port 3000

Solution:

# Kill the process using port 3000
lsof -ti:3000 | xargs kill

# Or use a different port
PORT=3001 npm run start:dev

Error: Can't resolve 'ts-loader'

Problem: Dev dependencies not installed

Solution:

npm install

This installs both dependencies and devDependencies.

📝 Quick Reference

Level Directory Command
Beginner 01-beginner/demo-beginner/ npm install && npm run start:dev
Intermediate 02-intermediate/code/ npm install && npm run start:dev
Advanced 03-advanced/code/ npm install && npm run start:dev
Examples Root (run from root) npm install && npm run start:dev

💡 Tips

  1. One at a time: Only run one level at a time (they all use port 3000)
  2. Install first: Always run npm install before npm run start:dev
  3. Check directory: Make sure you're in the correct directory before running commands
  4. Read README: Each level has a README with specific instructions
  1. Start with Beginner level
  2. Once comfortable, move to Intermediate
  3. Then try Advanced
  4. Finally, explore the Examples for a complete working application

Each level builds on the previous one, so follow them in order!