From f0d8e99b7e7f9407cc267e07bcd2f55e87c19b4d Mon Sep 17 00:00:00 2001
From: ItsOnlyBinary <git@itsonlybinary.com>
Date: Tue, 29 Aug 2023 20:11:11 +0100
Subject: [PATCH] Add base62 encode/decode to Misc.js

---
 src/helpers/Misc.js     | 32 ++++++++++++++++++++++++++++++++
 tests/unit/Misc.spec.js | 24 ++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/src/helpers/Misc.js b/src/helpers/Misc.js
index 4151d5891..0b2f5aca4 100644
--- a/src/helpers/Misc.js
+++ b/src/helpers/Misc.js
@@ -399,3 +399,35 @@ export function strCompare(a, b) {
         1 :
         -1;
 }
+
+const base62Digits = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
+export function base62Encode(_int) {
+    let int = _int;
+    let result = '';
+
+    if (int === 0) {
+        return base62Digits[0];
+    }
+
+    while (int > 0) {
+        result = base62Digits[int % base62Digits.length] + result;
+        int = Math.floor(int / base62Digits.length);
+    }
+
+    return result;
+}
+
+export function base62Decode(str) {
+    let result = 0;
+
+    for (let i = 0; i < str.length; i++) {
+        const charIdx = base62Digits.indexOf(str[i]);
+        if (charIdx < 0) {
+            return NaN;
+        }
+
+        result += charIdx * base62Digits.length ** (str.length - 1 - i);
+    }
+
+    return result;
+}
diff --git a/tests/unit/Misc.spec.js b/tests/unit/Misc.spec.js
index 30c66f258..17e1e1c6e 100644
--- a/tests/unit/Misc.spec.js
+++ b/tests/unit/Misc.spec.js
@@ -21,4 +21,28 @@ describe('Misc.js', () => {
             expect(doesMention).toEqual(c[2]);
         });
     });
+
+    it('base64Encode and Decode should match', () => {
+        const tests = [
+            [0, '0'],
+            [10, 'a'],
+            [61, 'Z'],
+            [62, '10'],
+            [55378008, '3KmlG'],
+        ];
+
+        tests.forEach(([key, value]) => {
+            const encoded = Misc.base62Encode(key);
+            const decoded = Misc.base62Decode(value);
+            expect(encoded).toEqual(value);
+            expect(decoded).toEqual(key);
+        });
+
+        for (let i = 0; i < 1000; i++) {
+            const random = Math.floor((Math.random() * 1000000));
+            const encoded = Misc.base62Encode(random);
+            const decoded = Misc.base62Decode(encoded);
+            expect(decoded).toEqual(random);
+        }
+    });
 });