feat(slug): URL-safe unique slugs for clients and projects

src/lib/slug/slug.test.ts

@@ -0,0 +1,75 @@
+import { describe, it, expect } from "vitest";
+import { slugify, uniqueSlug } from "@/lib/slug/slug";
+
+describe("slugify", () => {
+  it("lowercases and hyphenates words", () => {
+    expect(slugify("WFDash Web App")).toBe("wfdash-web-app");
+  });
+
+  it("strips punctuation", () => {
+    expect(slugify("Mega Infrastructure!")).toBe("mega-infrastructure");
+    expect(slugify("R&D / Tooling")).toBe("r-d-tooling");
+  });
+
+  it("collapses runs of separators", () => {
+    expect(slugify("a   b")).toBe("a-b");
+    expect(slugify("a---b")).toBe("a-b");
+  });
+
+  it("trims leading and trailing hyphens", () => {
+    expect(slugify("  -Hello-  ")).toBe("hello");
+  });
+
+  it("folds accents to plain letters", () => {
+    expect(slugify("Café Münster")).toBe("cafe-munster");
+  });
+
+  it("keeps digits", () => {
+    expect(slugify("Phase 2 Rollout")).toBe("phase-2-rollout");
+  });
+
+  it("caps length at 60 without a trailing hyphen", () => {
+    const result = slugify("x".repeat(80));
+    expect(result).toHaveLength(60);
+    expect(result.endsWith("-")).toBe(false);
+  });
+
+  it("returns a usable fallback when nothing survives", () => {
+    // A name of only punctuation, or of characters this does not transliterate,
+    // must still produce a valid slug — the field is required and pattern-checked.
+    expect(slugify("!!!")).toBe("item");
+    expect(slugify("")).toBe("item");
+  });
+
+  it("only ever emits characters the schema pattern allows", () => {
+    const pattern = /^[a-z0-9-]+$/;
+    for (const input of ["Ünïcødé ✨", "A_B_C", "100% Done", "  "]) {
+      expect(slugify(input)).toMatch(pattern);
+    }
+  });
+});
+
+describe("uniqueSlug", () => {
+  it("returns the base when it is free", () => {
+    expect(uniqueSlug("wfdash", [])).toBe("wfdash");
+    expect(uniqueSlug("wfdash", ["other"])).toBe("wfdash");
+  });
+
+  it("appends a counter when taken", () => {
+    expect(uniqueSlug("wfdash", ["wfdash"])).toBe("wfdash-2");
+    expect(uniqueSlug("wfdash", ["wfdash", "wfdash-2"])).toBe("wfdash-3");
+  });
+
+  it("skips gaps rather than reusing a freed slug", () => {
+    // "wfdash-2" was deleted. Reusing it would silently point old links at a
+    // different project, so keep counting past the highest taken value.
+    expect(uniqueSlug("wfdash", ["wfdash", "wfdash-3"])).toBe("wfdash-4");
+  });
+
+  it("keeps the result inside the 60-character limit", () => {
+    const base = "y".repeat(60);
+    const result = uniqueSlug(base, [base]);
+    expect(result.length).toBeLessThanOrEqual(60);
+    expect(result).not.toBe(base);
+  });
+});

src/lib/slug/slug.ts

@@ -0,0 +1,59 @@
+/**
+ * URL-safe identifiers for clients and projects.
+ *
+ * The schema declares slug with pattern ^[a-z0-9-]+$ and a 60-character cap,
+ * so anything this returns must satisfy both — including for input that is
+ * entirely punctuation or entirely non-Latin. A rejected create at the
+ * database, from a name the owner typed, is a bad failure.
+ */
+
+export const MAX_SLUG_LENGTH = 60;
+
+const FALLBACK = "item";
+
+export function slugify(input: string): string {
+  const slug = input
+    .normalize("NFD")
+    // Strip the combining diacritical marks NFD just split off, so "é"
+    // becomes "e" rather than "e" plus an accent that the next step deletes
+    // as punctuation. Written as escapes, not literal characters — the
+    // literal range is invisible in an editor and survives copy-paste badly.
+    .replace(/[\u0300-\u036f]/g, "")
+    .toLowerCase()
+    .replace(/[^a-z0-9]+/g, "-")
+    .replace(/-+/g, "-")
+    .replace(/^-|-$/g, "")
+    .slice(0, MAX_SLUG_LENGTH)
+    .replace(/-$/, "");
+
+  return slug || FALLBACK;
+}
+
+/**
+ * `base`, or `base-2`, `base-3`, … until one is free.
+ *
+ * Counts past the highest taken suffix rather than filling gaps: reusing a
+ * slug freed by a deletion would silently repoint old links — including any
+ * a client has bookmarked — at a different project.
+ */
+export function uniqueSlug(base: string, taken: string[]): string {
+  const used = new Set(taken);
+  if (!used.has(base)) return base;
+
+  let highest = 1;
+  for (const value of used) {
+    if (value === base) continue;
+    if (!value.startsWith(`${base}-`)) continue;
+    const suffix = Number(value.slice(base.length + 1));
+    if (Number.isInteger(suffix) && suffix > highest) highest = suffix;
+  }
+
+  let counter = highest + 1;
+  for (;;) {
+    const suffix = `-${counter}`;
+    const trimmed = base.slice(0, MAX_SLUG_LENGTH - suffix.length).replace(/-$/, "");
+    const candidate = `${trimmed}${suffix}`;
+    if (!used.has(candidate)) return candidate;
+    counter += 1;
+  }
+}