1 files changed, 23 insertions, 0 deletions
diff --git a/js/src/id/id.ts b/js/src/id/id.ts
new file mode 100644
index 000000000..a63716041
--- /dev/null
+++ b/js/src/id/id.ts
@@ -0,0 +1,23 @@
+import { ulid } from "ulid";
+import { z } from "zod";
+
+export namespace Identifier {
+  const prefixes = {
+    session: "ses",
+  } as const;
+
+  export function create(
+    prefix: keyof typeof prefixes,
+    given?: string,
+  ): string {
+    if (given) {
+      if (given.startsWith(prefixes[prefix])) return given;
+      throw new Error(`ID ${given} does not start with ${prefixes[prefix]}`);
+    }
+    return [prefixes[prefix], ulid()].join("_");
+  }
+
+  export function schema(prefix: keyof typeof prefixes) {
+    return z.string().startsWith(prefixes[prefix]);
+  }
+}