Build an Order State Machine

State pattern

Challenge 4 of Decouple EventsIntermediate~55 minFree

Model an order's lifecycle the way real systems do, as a state machine. Drive transitions from a table, expose what each state allows, record history, run entry actions on arrival (charge, email), and gate transitions with guards. The State pattern behind checkout flows and TCP.

5 steps

1. 1Transitions
2. 2What Can I Do Here?
3. 3History
4. 4Entry Actions
5. 5Guards