1 files changed, 50 insertions, 0 deletions
diff --git a/web/source/settings/lib/domain-block.js b/web/source/settings/lib/domain-block.js
new file mode 100644
index 000000000..d13c029d2
--- /dev/null
+++ b/web/source/settings/lib/domain-block.js
@@ -0,0 +1,50 @@
+/*
+	GoToSocial
+	Copyright (C) 2021-2023 GoToSocial Authors admin@gotosocial.org
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+"use strict";
+
+const isValidDomain = require("is-valid-domain");
+const psl = require("psl");
+
+function isValidDomainBlock(domain) {
+	return isValidDomain(domain, {
+		/* 
+			Wildcard prefix *. can be stripped since it's equivalent to not having it,
+			but wildcard anywhere else in the domain is not handled by the backend so it's invalid.
+		*/
+		wildcard: false,
+		allowUnicode: true
+	});
+}
+
+/* 
+	Still can't think of a better function name for this,
+	but we're checking a domain against the Public Suffix List <https://publicsuffix.org/>
+	to see if we should suggest removing subdomain(s) since they're likely owned/ran by the same party
+	social.example.com -> suggests example.com
+*/
+function hasBetterScope(domain) {
+	const lookup = psl.get(domain);
+	if (lookup && lookup != domain) {
+		return lookup;
+	} else {
+		return false;
+	}
+}
+
+module.exports = { isValidDomainBlock, hasBetterScope };
+\ No newline at end of file