From da766f364ccae7199c3de5fbd7e21afa0ad3b601 Mon Sep 17 00:00:00 2001
From: Sirz Benjie <142067137+SirzBenjie@users.noreply.github.com>
Date: Thu, 18 Sep 2025 07:52:15 -0500
Subject: [PATCH] [Tests] Cleanup `getCookie` and add many unit tests (#6562)

Cleanup `getCookie` and add many unit tests
---
 src/utils/cookies.ts       | 16 +++++-----
 test/utils/cookies.test.ts | 62 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 9 deletions(-)
 create mode 100644 test/utils/cookies.test.ts

diff --git a/src/utils/cookies.ts b/src/utils/cookies.ts
index e16d9d78556..407bd75da14 100644
--- a/src/utils/cookies.ts
+++ b/src/utils/cookies.ts
@@ -17,19 +17,17 @@ export function removeCookie(cName: string): void {
 
 export function getCookie(cName: string): string {
   // check if there are multiple cookies with the same name and delete them
-  if (document.cookie.split(";").filter(c => c.includes(cName)).length > 1) {
+  if (document.cookie.split(";").filter(c => c.trim().includes(cName)).length > 1) {
     removeCookie(cName);
     return "";
   }
   const name = `${cName}=`;
-  const ca = document.cookie.split(";");
-  for (let c of ca) {
-    // ⚠️ DO NOT REPLACE THIS WITH C = C.TRIM() - IT BREAKS IN NON-CHROMIUM BROWSERS ⚠️
-    while (c.charAt(0) === " ") {
-      c = c.substring(1);
-    }
-    if (c.indexOf(name) === 0) {
-      return c.substring(name.length, c.length);
+  const cookieArray = document.cookie.split(";");
+  // Check all cookies in the document and see if any of them match, grabbing the first one whose value lines up
+  for (const cookie of cookieArray) {
+    const cookieTrimmed = cookie.trim();
+    if (cookieTrimmed.startsWith(name)) {
+      return cookieTrimmed.slice(name.length, cookieTrimmed.length);
     }
   }
   return "";
diff --git a/test/utils/cookies.test.ts b/test/utils/cookies.test.ts
new file mode 100644
index 00000000000..a5ea248c236
--- /dev/null
+++ b/test/utils/cookies.test.ts
@@ -0,0 +1,62 @@
+import { getCookie } from "#utils/cookies";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+describe("Unit Tests - cookies.ts", () => {
+  describe("getCookie", () => {
+    const cookieStart = document.cookie;
+    beforeEach(() => {
+      // clear cookie before each test
+      document.cookie = "";
+    });
+
+    afterEach(() => {
+      // restore original cookie after each test
+      document.cookie = cookieStart;
+    });
+    /**
+     * Spies on `document.cookie` and replaces its value with the provided string.
+     */
+    function setDocumentCookie(value: string) {
+      vi.spyOn(document, "cookie", "get").mockReturnValue(value);
+    }
+    it("returns the value of a single cookie", () => {
+      setDocumentCookie("foo=bar");
+      expect(getCookie("foo")).toBe("bar");
+    });
+
+    it("returns empty string if cookie is not found", () => {
+      setDocumentCookie("foo=bar");
+      expect(getCookie("baz")).toBe("");
+    });
+
+    it("returns the value when multiple cookies exist", () => {
+      setDocumentCookie("foo=bar; baz=qux");
+      expect(getCookie("baz")).toBe("qux");
+    });
+
+    it("trims leading spaces in cookies", () => {
+      setDocumentCookie("foo=bar;  baz=qux");
+      expect(getCookie("baz")).toBe("qux");
+    });
+
+    it("returns the value of the first matching cookie if only one exists", () => {
+      setDocumentCookie("foo=bar; test=val");
+      expect(getCookie("foo")).toBe("bar");
+    });
+
+    it("returns empty string if document.cookie is empty", () => {
+      setDocumentCookie("");
+      expect(getCookie("foo")).toBe("");
+    });
+
+    it("handles cookies that aren't separated with a space", () => {
+      setDocumentCookie("foo=bar;baz=qux;quux=corge;grault=garply");
+      expect(getCookie("baz")).toBe("qux");
+    });
+
+    it("handles cookies that may have leading tab characters", () => {
+      setDocumentCookie("foo=bar;\tbaz=qux");
+      expect(getCookie("baz")).toBe("qux");
+    });
+  });
+});