★ Mini-capstone A · after Module 6 · quadrant one of the final diagram
Trace the request
One tap in a coffee app, followed all the way down and back. This time you build the trace yourself, make the system’s calls at the checkpoints, then break the finished thing three ways. You’ve learned every piece of this already. What’s new is running it end to end yourself.
Fig. A — the request path, assembling1 / 9
1
You tap “Place order”client
In the browser, client-side JavaScript gathers your cart into an object: { drink: "latte", size: "large", quantity: 1 }. Nothing has left your machine yet.
2
What happens next?
Step 1 is on the rail. Tap the card that comes next.