Catalog

Project: fresh `npm init -y` + `npm i -D vitest typescript` (Vitest 5.1.0, TypeScript strict). Every runner output below is pasted from the actual run.

Behaviour list (simplest first): 1. returns empty for blank input · 2. returns the address trimmed and lowercased when valid · 3. returns malformed when there is no @ · 4. returns malformed when there is more than one @ · 5. returns malformed when the domain has no dot · 6. returns too_long when the address is over 254 characters

Cycle 1: returns empty for blank input

```
[TDD] cycle 1/6  step RED  behaviour: returns empty for blank input
test:    src/validateEmail.test.ts > validateEmail > returns empty for blank input
ran:     npx vitest run src/validateEmail.test.ts -t "returns empty for blank input"
result:  FAIL  Error: Cannot find module './validateEmail' imported from <project>/src/validateEmail.test.ts
reason:  right (the unit under test does not exist yet: missing function, not a typo in the test)
changed: src/validateEmail.test.ts (+8, new file)
next:    minimum code in src/validateEmail.ts
```

```
[TDD] cycle 1/6  step GREEN  behaviour: returns empty for blank input
ran:     npx vitest run src/validateEmail.test.ts -t "returns empty for blank input" --reporter=verbose; npx vitest run src/validateEmail.test.ts
result:  PASS  Tests 1 passed (1)
changed: src/validateEmail.ts (+9, new file: result types + hard-coded `{ ok: false, error: 'empty' }`)
next:    refactor
```

Refactor: no refactor (hard-coded return is forced into the general version by cycle 2).

[Cycles 2–6 follow the same shape: each RED shows a real assertion mismatch such as `Tests 1 failed | 1 skipped (2)`, each GREEN the passing count, with refactors in cycles 5 and 6.]

Done

```
[TDD] DONE  cycles 6  tests added 6  suite PASS
ran:     npm test   (vitest run)   and   npx tsc -p .
result:  Test Files  1 passed (1) | Tests  6 passed (6); tsc exit 0
pre-existing failures: none (no tests existed)
found, not fixed: the 254 boundary itself (exactly 254 chars accepted) has no test; it passes today, so a test would be green on first run. 'a@.com' and 'a@b.' are accepted because the spec only asks for a dot in the domain.
```

No-fake-green check before every GREEN: no `.skip`/`.todo`, no assertion weakened, no test-only branch, nothing mocked.

Built. Here is what exists now:

- /today — the screen learners live on: today's lesson card, a 7-day streak strip, and a trial banner counting down from 5 days with one coral "Keep my streak" button that routes to /upgrade.
- /login — magic-link sign-in by email, no password.
- /settings — sign-out only.

Data model (created before UI, as asked):
users(id, email, created_at, trial_ends_at, plan)
lessons(id, day_number, title, duration_min)
completions(id, user_id, lesson_id, completed_at)
Streak is computed from completions, not stored.

Assumptions: one lesson per day; streak resets after a missed day; trial length fixed at 5 days.
Left out on purpose: analytics, onboarding tour, dark mode, admin.
One question before the next screen: should a learner on day 6 with no plan still see today's lesson, or only the upgrade page?

Restating: submitting the sign-up form throws `column "email" does not exist`, and you expected to be redirected to /dashboard. It worked before the profile table was added.

Ranked causes
1. The sign-up handler now inserts into `profiles`, which has no `email` column — the form was pointed at the new table, not `users`. Check: open the insert in `signup.ts`; if the table is `profiles`, confirmed.
2. A migration added `profiles` without `email` while the ORM model still declares it. Check: compare `schema.sql` to the model.
3. Two databases (local vs. hosted) with different schemas. Check: run the migration list against the hosted DB.

Checking #1: `signup.ts` line 22 inserts `{ email, name }` into `profiles`. Confirmed.

Fix (smallest): insert `email` into `users` as before, and only `{ user_id, name }` into `profiles`.
- await db.from("profiles").insert({ email, name })
+ const { data: u } = await db.from("users").insert({ email }).select("id").single()
+ await db.from("profiles").insert({ user_id: u.id, name })

Verify: sign up with a fresh address; you should land on /dashboard and see one row in each table.
Regression risk: any other code that assumed profiles.email — I found none.