slug.ts · Source

slug.tsapps/api/src/modules/forms/slug.tsraw ← forms2,313 B← Back to the app
1/**
2 * TASK-0106 §3 — form slug generation.
3 *
4 * Kebab-case from the form name, ≤ 50 chars (LIMITS.MAX_SLUG), with a
5 * deterministic `-2`/`-3`/… suffix on collision. The collision check +
6 * insert is NOT atomic here — `FormsService` wraps the whole thing in a
7 * transaction and the `forms.slug` unique index is the final arbiter
8 * (P2002 → regenerate, max 3 attempts; spec §Security "race-safe").
9 */
10import { Prisma } from "@prisma/client";
11 
12/** A slug the client may provide (already kebab-shaped by its own UI). */
13export const SLUG_INPUT_REGEX = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;
14 
15const MAX_SLUG = 50;
16 
17/** Kebab-case a display name: lowercase, non-alphanumerics → `-`. */
18export function kebabSlug(name: string): string {
19  return name
20    .toLowerCase()
21    .normalize("NFKD")
22    .replace(/[^a-z0-9]+/g, "-")
23    .replace(/^-+|-+$/g, "");
24}
25 
26/** A valid slug candidate: 2..50 chars, kebab. (Empty names → ""). */
27export function normalizeSlug(name: string): string {
28  return kebabSlug(name).slice(0, MAX_SLUG).replace(/-+$/g, "");
29}
30 
31/**
32 * `slug` with the next free collision suffix: `slug` itself when free,
33 * else `slug-2`, `slug-3`, … (spec: "-2/-3 suffix on collision").
34 *
35 * `prisma` is the live client (or a transaction); `taken(slugs)` must
36 * report which candidates are already used platform-wide (one query).
37 */
38export async function nextFreeSlug(
39  base: string,
40  taken: (slugs: string[]) => Promise<Set<string>>
41): Promise<string> {
42  const clean = base || "form";
43  const first = await taken([clean]);
44  if (!first.has(clean)) return clean;
45  for (let n = 2; ; n++) {
46    // Keep the total ≤ MAX_SLUG (suffix eats into the budget).
47    const candidate = `${clean.slice(0, MAX_SLUG - String(n).length - 1)}-${n}`;
48    const used = await taken([candidate]);
49    if (!used.has(candidate)) return candidate;
50    if (n > 1000) throw new Error(`slug generation exhausted for ${clean}`);
51  }
52}
53 
54/** True when a Prisma error is the `forms.slug` unique-constraint violation. */
55export function isSlugConstraintError(err: unknown): boolean {
56  return (
57    err instanceof Prisma.PrismaClientKnownRequestError &&
58    err.code === "P2002" &&
59    (Array.isArray(err.meta?.target)
60      ? (err.meta.target as string[]).includes("slug")
61      : err.meta?.target === "slug")
62  );
63}
64