feat(config)!: unsafe domain toggle (#11588)

lib/utils/valid-host.js

@@ -0,0 +1,16 @@
+/**
+ * Check if a sub-domain is valid
+ * @param {String} hostname sub-domain
+ * @returns {Boolean} true if valid
+ */
+const isValidHost = (hostname) => {
+    if (typeof hostname !== 'string') {
+        return false;
+    }
+    const regex = /^[a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?$/;
+    return regex.test(hostname);
+};
+
+module.exports = {
+    isValidHost,
+};