Fix Wrong Answer for problems with top-level JSON string output

[alexandramartinez]

Summary

Fixes #12 — problems whose expected output is a top-level JSON string (e.g. concatenate-employee-names) were impossible to solve. Submit always returned "Wrong Answer" because the actual output was shown with its surrounding quotes stripped, so it never matched the quoted expected value.

Root cause

The backend at dwlbackend.onrender.com returns output as the decoded value, not serialized text:

• application/json → a real JSON value ({"output":"Alice, Bob, Carol"}, {"output":3}, {"output":{...}})
• non-JSON formats (application/csv, xml, …) → the already-rendered text as a string

The proxy in app/api/execute/route.ts did typeof value === "string" ? value : JSON.stringify(value), so a top-level JSON string was passed through unquoted. The submit comparison in Workspace.tsx then re-serialized the quoted expected value but kept the unquoted actual value — never equal.

Fix

Serialize based on the script's declared output format:

• JSON output → always JSON.stringify the value, so a top-level string keeps its quotes ("Alice, Bob, Carol").
• Non-JSON output (csv/xml/text) → pass string values through verbatim, since the backend already rendered them.

Verification

Tested end-to-end against a local dev server with the real problem seeded into MongoDB, driving the actual /api/execute route and the real normalize() comparison from Workspace.tsx:

Before (reproduces the bug):

✗ Wrong Answer
Test 1: ✗ Failed   Expected: "Alice, Bob, Carol"   Got: Alice, Bob, Carol
Test 2: ✗ Failed   Expected: "Dave"                Got: Dave

After:

✅ Accepted
Test 1: ✓ Passed   Expected: "Alice, Bob, Carol"   Got: "Alice, Bob, Carol"
Test 2: ✓ Passed   Expected: "Dave"                Got: "Dave"

No regressions confirmed against live backend responses:

Output	Result
JSON string	"Alice, Bob, Carol" (quoted) ✓
JSON number	3 ✓
JSON object	pretty-printed object ✓
CSV	a,b\n1,2 (raw, no quotes) ✓

npx tsc --noEmit passes clean.

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated (UTC)
dwcode	Ready	Preview, Comment	Jul 17, 2026 6:18pm

[f-schnabel]

LGTM!