Duplicate-key error detection duplicated across 4 routes with inconsistent matching

[dobby-coder]

Problem

"Did this insert fail because the unique constraint tripped?" is detected in four places, each slightly differently. The members route in particular only matches `unique` and misses the `duplicate key` substring postgres emits on its main error message — so a unique-violation under that wording becomes a 500 to the user instead of a friendly 409.

File	Pattern
`src/routes/(admin)/admin/organizations/+page.server.ts:104`	helper `isDuplicateKeyError` — checks `duplicate key` OR `unique` on message + cause
`src/routes/(admin)/admin/organizations/[id]/+page.server.ts:184`	inline regex `/duplicate key|unique/i` on message + cause
`src/routes/(portal)/portal/members/+page.server.ts:34`	`err.message.includes('unique')` only — misses `duplicate key` path
`src/routes/(marketing)/register/+page.server.ts:81-83`	inline includes on message + cause

Suggested fix

Extract a single helper (e.g. `src/lib/server/services/_errors.ts`):

```ts
export function isUniqueViolation(err: unknown): boolean {
if (!(err instanceof Error)) return false;
const msg = err.message ?? '';
const cause = (err as { cause?: { message?: string } }).cause?.message ?? '';
const hay = `${msg}\n${cause}`.toLowerCase();
return hay.includes('duplicate key') || hay.includes('unique');
}
```

Then replace the four call sites. The members route gets correct `duplicate key` coverage for free.

Why this matters

The members-route gap is the user-visible part: portal users adding a duplicate member email today may see an unexpected 500 instead of the intended 409 message, depending on which postgres error path fires.

Test plan

• Unit test the helper against shaped postgres error objects (both `duplicate key` wording and `unique constraint` wording on `message` and on `cause.message`).
• Verify all four call sites still produce the same form-error shape.

[dobby-coder]

/dobby

[dobby-coder]

Dobby is on it! Dobby will extract the duplicate-key detection into a single helper, fix the members route gap, and add unit tests as requested. Dobby will post a plan shortly.

[dobby-coder]

Plan

Approach: extract the duplicate-key check into one helper, replace all four call sites, add unit tests.

Files to add:

• src/lib/server/services/errors.ts — isUniqueViolation(err: unknown): boolean. Checks both err.message and err.cause.message (case-insensitive) for either duplicate key or unique.
• tests/unit/errors.test.ts — unit tests covering both wordings, both on message and on cause.message, plus non-Error inputs.

Files to modify:

• src/routes/(admin)/admin/organizations/+page.server.ts — drop local isDuplicateKeyError + errMessage, import shared helper.
• src/routes/(admin)/admin/organizations/\[id\]/+page.server.ts — replace inline regex.
• src/routes/(portal)/portal/members/+page.server.ts — replace narrow includes('unique') check; this is the user-visible fix.
• src/routes/(marketing)/register/+page.server.ts — replace inline includes block.

Verification: npx vitest run, npm run check, and npx vite build (with NODE_OPTIONS=--max-old-space-size=3072 per repo notes).

Risks: the helper is a non-route module under src/lib/server/services/, so SvelteKit's route-export whitelist doesn't apply. Call sites keep the same conditional branch structure, so failure shape is unchanged for existing wordings.

Closes #89.

[dobby-coder]

PR opened: #92 — unifies the duplicate-key check, closes the members-route 500 gap, includes 8 new unit tests.