From 0746394d76b05563b7c6e0ea6230aaf182fe2aba Mon Sep 17 00:00:00 2001
From: streamich <streamich@gmail.com>
Date: Tue, 5 Dec 2023 02:30:31 +0100
Subject: [PATCH] =?UTF-8?q?feat(util):=20=F0=9F=8E=B8=20add=20Base64url=20?=
 =?UTF-8?q?encoder=20and=20decoder?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../base64/__tests__/decode-base64url.spec.ts | 20 ++++++++++++++++
 .../base64/__tests__/encode-base64url.spec.ts | 23 +++++++++++++++++++
 src/util/base64/createFromBase64.ts           | 14 +++++++++--
 src/util/base64/createToBase64.ts             |  5 +---
 src/util/base64/fromBase64Url.ts              |  3 +++
 src/util/base64/toBase64Url.ts                |  3 +++
 6 files changed, 62 insertions(+), 6 deletions(-)
 create mode 100644 src/util/base64/__tests__/decode-base64url.spec.ts
 create mode 100644 src/util/base64/__tests__/encode-base64url.spec.ts
 create mode 100644 src/util/base64/fromBase64Url.ts
 create mode 100644 src/util/base64/toBase64Url.ts

diff --git a/src/util/base64/__tests__/decode-base64url.spec.ts b/src/util/base64/__tests__/decode-base64url.spec.ts
new file mode 100644
index 0000000000..3344250fc3
--- /dev/null
+++ b/src/util/base64/__tests__/decode-base64url.spec.ts
@@ -0,0 +1,20 @@
+import {toBase64} from '../toBase64';
+import {fromBase64Url} from '../fromBase64Url';
+
+const generateBlob = (): Uint8Array => {
+  const length = Math.floor(Math.random() * 100);
+  const uint8 = new Uint8Array(length);
+  for (let i = 0; i < length; i++) {
+    uint8[i] = Math.floor(Math.random() * 256);
+  }
+  return uint8;
+};
+
+test('works', () => {
+  for (let i = 0; i < 100; i++) {
+    const blob = generateBlob();
+    const encoded = toBase64(blob).replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
+    const decoded2 = fromBase64Url(encoded);
+    expect(decoded2).toEqual(blob);
+  }
+});
diff --git a/src/util/base64/__tests__/encode-base64url.spec.ts b/src/util/base64/__tests__/encode-base64url.spec.ts
new file mode 100644
index 0000000000..1d2880f21b
--- /dev/null
+++ b/src/util/base64/__tests__/encode-base64url.spec.ts
@@ -0,0 +1,23 @@
+import {toBase64Url} from '../toBase64Url';
+
+const generateBlob = (): Uint8Array => {
+  const length = Math.floor(Math.random() * 100) + 1;
+  const uint8 = new Uint8Array(length);
+  for (let i = 0; i < length; i++) {
+    uint8[i] = Math.floor(Math.random() * 256);
+  }
+  return uint8;
+};
+
+test('works', () => {
+  for (let i = 0; i < 100; i++) {
+    const blob = generateBlob();
+    const expected = Buffer.from(blob).toString('base64');
+    const base64url = toBase64Url(blob, blob.length);
+    let encoded = base64url.replace(/-/g, '+').replace(/_/g, '/');
+    const mod = encoded.length % 4;
+    if (mod === 2) encoded += '==';
+    else if (mod === 3) encoded += '=';
+    expect(encoded).toEqual(expected);
+  }
+});
diff --git a/src/util/base64/createFromBase64.ts b/src/util/base64/createFromBase64.ts
index e528434622..5f4922f4e4 100644
--- a/src/util/base64/createFromBase64.ts
+++ b/src/util/base64/createFromBase64.ts
@@ -2,7 +2,7 @@ import {alphabet} from './constants';
 
 const E = '=';
 
-export const createFromBase64 = (chars: string = alphabet) => {
+export const createFromBase64 = (chars: string = alphabet, noPadding: boolean = false) => {
   if (chars.length !== 64) throw new Error('chars must be 64 characters long');
   let max = 0;
   for (let i = 0; i < chars.length; i++) max = Math.max(max, chars.charCodeAt(i));
@@ -12,7 +12,17 @@ export const createFromBase64 = (chars: string = alphabet) => {
 
   return (encoded: string): Uint8Array => {
     if (!encoded) return new Uint8Array(0);
-    const length = encoded.length;
+    let length = encoded.length;
+    if (noPadding) {
+      const mod = length % 4;
+      if (mod === 2) {
+        encoded += '==';
+        length += 2;
+      } else if (mod === 3) {
+        encoded += '=';
+        length += 1;
+      }
+    }
     if (length % 4 !== 0) throw new Error('Base64 string length must be a multiple of 4');
     const mainLength = encoded[length - 1] !== E ? length : length - 4;
     let bufferLength = (length >> 2) * 3;
diff --git a/src/util/base64/createToBase64.ts b/src/util/base64/createToBase64.ts
index fdbce4984f..6a8b8e62e1 100644
--- a/src/util/base64/createToBase64.ts
+++ b/src/util/base64/createToBase64.ts
@@ -1,9 +1,6 @@
 import {alphabet} from './constants';
 
-const E = '=';
-const EE = '==';
-
-export const createToBase64 = (chars: string = alphabet) => {
+export const createToBase64 = (chars: string = alphabet, E: string = '=', EE: string = '==') => {
   if (chars.length !== 64) throw new Error('chars must be 64 characters long');
 
   const table = chars.split('');
diff --git a/src/util/base64/fromBase64Url.ts b/src/util/base64/fromBase64Url.ts
new file mode 100644
index 0000000000..12be59f819
--- /dev/null
+++ b/src/util/base64/fromBase64Url.ts
@@ -0,0 +1,3 @@
+import {createFromBase64} from './createFromBase64';
+
+export const fromBase64Url = createFromBase64('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_', true);
diff --git a/src/util/base64/toBase64Url.ts b/src/util/base64/toBase64Url.ts
new file mode 100644
index 0000000000..c638705583
--- /dev/null
+++ b/src/util/base64/toBase64Url.ts
@@ -0,0 +1,3 @@
+import {createToBase64} from './createToBase64';
+
+export const toBase64Url = createToBase64('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_', '', '');