typescriptEASYCODING
Warm up with generic Result type
Easy TypeScript arena: generics, error modeling, and safe unwrap helpers
XP reward
95
Coins
8
Target time
15m
An API client currently throws inconsistently and needs typed success/error results. You are working inside a TypeScript monorepo, and the arena only clears when the result is safe, deterministic, and explainable.
Learning objective
Learn to apply generics, error modeling, and safe unwrap helpers in a TypeScript monorepo while explaining the invariant, safety constraints, and hidden edge cases.
Mission order
Functions return either data or structured error details with a status code. Implement the direct solution first, then document the one edge case that can break it. Submit the solution plus enough reasoning to pass hidden edge cases.Visible checks
sample case
Expected: 2
empty input
Expected: 0
Clear requirements
- Demonstrates generics, error modeling, and safe unwrap helpers
- Handles the visible sample and hidden edge cases
- Keeps output deterministic and explainable
- Avoids unsafe dynamic execution
Secure validation contract
Judge type
CODING
Complexity target
Readable O(n) or O(n log n) baseline
Workspace
Code editor
typescriptsafe mock judge
Charging editor core
Test Results
Run the visible checks when your first pass is ready.
Clear Protocol
1Read the scenario and restate the expected output shape.
2Run visible checks before chasing hidden edge cases.
3Use Genie for one nudge if stuck, then explain the invariant.
4Submit only when the result is deterministic and safe.
Rewards
XP
95
Coins
8
Mission Route
Hints
Hints are metered and logged for No Hint Hero runs.
Genie Mentor Core
Hint protocol / contextual guardrails active
Progressive hints
Failed-test aware
Solution guarded
Mission: typescript-easy-generic-result0 attempts0 failed tests0 hints used
Progressive hint depth
Genie: Genie online. I use your mission, attempts, failed tests, hints, and path context to coach the next rep without dumping answers first.