Briefle words · Code & architecture
Happy path
The default scenario where every input is valid, nothing goes wrong and the user reaches their goal.
Say it to an AI
TypeScript dispatchShipment(order) that books a courier for an order. Validate with guard clauses at the top (unpaid, no items, missing postcode), each throwing its own error, then keep the happy path flat at the bottom. No nested if/else.
How an expert would brief the stronger version of “Shipment dispatch”.
See it
Try it as a puzzle →A pull request adds the function that books a courier for a paid order in a delivery platform.
Why: A's happy path, 'createLabel' then 'courier.book', is the last two lines at the top level; in B it is buried in the middle.
More ways experts use it
Draw the split-a-bill user flow: the happy path in four steps, and under each step the edge case that can break it (uneven split, friend not on the app, unpaid after 7 days, decline), with the rule for each.
User flow diagram · Product & specsMap the send-money flow: happy path Amount → Recipient → Confirm → Sent, then the main unhappy paths under the step where each happens (low balance, unknown recipient, Face ID failure, bank decline), each with the recovery action the user gets.
Money transfer flow · Product & specs
Related words
Room 1 · Essentials
Learn “Happy path” in a five-minute lesson