How does Docker Compose simplify running a Node.js application alongside its dependencies (like a database and Redis) during local development?

Docker Compose defines multiple related services (the Node.js app, a PostgreSQL database, a Redis cache) in a single docker-compose.yml file, including their networking (services can reach each other by service name), volumes (for persisting database data across restarts), and startup dependencies -- letting a developer spin up an entire multi-service local development environment with one command, rather than manually installing and configuring each dependency directly on their machine.

# docker-compose.yml
services:
  app:
    build: .
    ports: ['3000:3000']
    depends_on: [db, redis]
    environment:
      - DATABASE_URL=postgres://user:pass@db:5432/mydb
      - REDIS_URL=redis://redis:6379
  db:
    image: postgres:16
    volumes: ['pgdata:/var/lib/postgresql/data']
  redis:
    image: redis:7
volumes:
  pgdata: