From 3f93924448074fe69f850195fa010da9c891b387 Mon Sep 17 00:00:00 2001
From: Marcos Passos <marcospassos@users.noreply.github.com>
Date: Fri, 16 Dec 2022 10:06:08 -0300
Subject: [PATCH] Fix decoding of UTF8-encoded tokens (#297)

---
 src/base64Url.ts       | 14 ++++++++++++--
 test/base64Url.test.ts |  7 +------
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/base64Url.ts b/src/base64Url.ts
index f48518ca..cc5fb0e4 100644
--- a/src/base64Url.ts
+++ b/src/base64Url.ts
@@ -10,9 +10,19 @@ function base64Escape(value: string): string {
 }
 
 export function base64UrlEncode(value: string): string {
-    return base64Escape(window.btoa(value));
+    return base64Escape(
+        window.btoa(
+            window.encodeURIComponent(value)
+                .replace(/%([0-9A-F]{2})/g, (_, p1) => String.fromCharCode(Number.parseInt(p1, 16))),
+        ),
+    );
 }
 
 export function base64UrlDecode(value: string): string {
-    return window.atob(base64Unescape(value));
+    return window.decodeURIComponent(
+        Array.prototype.map.call(
+            window.atob(base64Unescape(value)),
+            (char: string) => `%${(`00${char.charCodeAt(0).toString(16)}`).slice(-2)}`,
+        ).join(''),
+    );
 }
diff --git a/test/base64Url.test.ts b/test/base64Url.test.ts
index 8e177330..69095f0d 100644
--- a/test/base64Url.test.ts
+++ b/test/base64Url.test.ts
@@ -3,12 +3,6 @@ import {base64UrlDecode, base64UrlEncode} from '../src/base64Url';
 describe('A base64 URL encoder/decoder function', () => {
     const encodeTests = [
         ['000000', 'MDAwMDAw'],
-        ['\0\0\0\0', 'AAAAAA'],
-        ['\xff', '_w'],
-        ['\xff\xff', '__8'],
-        ['\xff\xff\xff', '____'],
-        ['\xff\xff\xff\xff', '_____w'],
-        ['\xfb', '-w'],
         ['', ''],
         ['f', 'Zg'],
         ['fo', 'Zm8'],
@@ -16,6 +10,7 @@ describe('A base64 URL encoder/decoder function', () => {
         ['foob', 'Zm9vYg'],
         ['fooba', 'Zm9vYmE'],
         ['foobar', 'Zm9vYmFy'],
+        ['Jacaré', 'SmFjYXLDqQ'],
     ];
 
     it.each(encodeTests)('should encode "%s" as "%s"', (decoded: string, encoded: string) => {