1 files changed, 20 insertions, 0 deletions
diff --git a/packages/backend/src/misc/generate-invite-code.ts b/packages/backend/src/misc/generate-invite-code.ts
new file mode 100644
index 0000000000..617b27361d
--- /dev/null
+++ b/packages/backend/src/misc/generate-invite-code.ts
@@ -0,0 +1,20 @@
+import { secureRndstr } from './secure-rndstr.js';
+
+const CHARS = '23456789ABCDEFGHJKLMNPQRSTUVWXYZ'; // [0-9A-Z] w/o [01IO] (32 patterns)
+
+export function generateInviteCode(): string {
+	const code = secureRndstr(8, {
+		chars: CHARS,
+	});
+
+	const uniqueId = [];
+	let n = Math.floor(Date.now() / 1000 / 60);
+	while (true) {
+		uniqueId.push(CHARS[n % CHARS.length]);
+		const t = Math.floor(n / CHARS.length);
+		if (!t) break;
+		n = t;
+	}
+
+	return code + uniqueId.reverse().join('');
+}