Merge fix/client-id-insecure-context for client-side ids

tests/client-id.test.ts

@@ -0,0 +1,45 @@
+import assert from "node:assert/strict";
+import { webcrypto } from "node:crypto";
+import { describe, it } from "node:test";
+import { z } from "zod";
+import { createClientId } from "../src/frontend/utils/client-id.js";
+
+const uuidV4 = /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/;
+
+describe("client id", () => {
+  it("uses crypto.randomUUID when the context provides it", () => {
+    const id = createClientId({
+      getRandomValues: () => {
+        throw new Error("fallback must not be used");
+      },
+      randomUUID: () => "11111111-2222-4333-8444-555555555555",
+    });
+    assert.equal(id, "11111111-2222-4333-8444-555555555555");
+  });
+
+  it("falls back to getRandomValues outside a secure context", () => {
+    const insecure = {
+      getRandomValues: webcrypto.getRandomValues.bind(webcrypto),
+    } as Pick<Crypto, "getRandomValues">;
+    const ids = new Set<string>();
+    for (let index = 0; index < 200; index += 1) {
+      const id = createClientId(insecure);
+      assert.match(id, uuidV4);
+      assert.equal(z.string().uuid().safeParse(id).success, true);
+      ids.add(id);
+    }
+    assert.equal(ids.size, 200);
+  });
+
+  it("sets version and variant bits regardless of the random bytes", () => {
+    const allOnes = {
+      getRandomValues: <T extends ArrayBufferView | null>(array: T) => {
+        if (array instanceof Uint8Array) {
+          array.fill(0xff);
+        }
+        return array;
+      },
+    } as Pick<Crypto, "getRandomValues">;
+    assert.equal(createClientId(allOnes), "ffffffff-ffff-4fff-bfff-ffffffffffff");
+  });
+});