From c404c67f0e1b6d30028f6ad10a02c310b5456930 Mon Sep 17 00:00:00 2001
From: shaurya703 <kesar.shaurya@gmail.com>
Date: Fri, 14 Aug 2026 12:27:10 +0530
Subject: [PATCH] fix: return undefined from getPrefix/parseId for non-string
 input

---
 CHANGELOG.md          |  4 ++++
 src/utils/validate.ts |  2 ++
 test/validate.test.ts | 14 ++++++++++++++
 3 files changed, 20 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 22dd339..5e88ca9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- `getPrefix(value, separator?)` and `parseId(value, separator?)` now return `undefined` for non-string input instead of throwing, matching `isId` and `getTimestamp`.
+
 ## [1.1.0] - 2026-08-16
 
 ### Added
diff --git a/src/utils/validate.ts b/src/utils/validate.ts
index b864bec..66a2e16 100644
--- a/src/utils/validate.ts
+++ b/src/utils/validate.ts
@@ -22,6 +22,7 @@ export function getPrefix(
   value: string,
   separator: string = DEFAULT_SEPARATOR,
 ): string | undefined {
+  if (typeof value !== "string") return undefined;
   const index = value.indexOf(separator);
   return index > 0 ? value.slice(0, index) : undefined;
 }
@@ -30,6 +31,7 @@ export function parseId(
   value: string,
   separator: string = DEFAULT_SEPARATOR,
 ): { prefix: string; id: string } | undefined {
+  if (typeof value !== "string") return undefined;
   const index = value.indexOf(separator);
   if (index > 0) {
     return {
diff --git a/test/validate.test.ts b/test/validate.test.ts
index 4fa98ee..fe911fe 100644
--- a/test/validate.test.ts
+++ b/test/validate.test.ts
@@ -54,6 +54,13 @@ describe("getPrefix()", () => {
   it("supports a custom separator", () => {
     expect(getPrefix("user.abc", ".")).toBe("user");
   });
+
+  it("returns undefined for non-strings", () => {
+    expect(getPrefix(null as unknown as string)).toBeUndefined();
+    expect(getPrefix(undefined as unknown as string)).toBeUndefined();
+    expect(getPrefix(42 as unknown as string)).toBeUndefined();
+    expect(getPrefix({} as unknown as string)).toBeUndefined();
+  });
 });
 
 describe("parseId()", () => {
@@ -72,4 +79,11 @@ describe("parseId()", () => {
   it("supports a custom separator", () => {
     expect(parseId("user.abc", ".")).toEqual({ prefix: "user", id: "abc" });
   });
+
+  it("returns undefined for non-strings", () => {
+    expect(parseId(null as unknown as string)).toBeUndefined();
+    expect(parseId(undefined as unknown as string)).toBeUndefined();
+    expect(parseId(42 as unknown as string)).toBeUndefined();
+    expect(parseId({} as unknown as string)).toBeUndefined();
+  });
 });