updated blocklist check logic to prevent adding a subdomain if a higher-level domain is already blocked

lib/utils.js

@@ -17,6 +17,24 @@ export const sleep = (ms = 350) =>
 export const isValidDomain = (value) =>
   /^(?!-)[A-Za-z0-9-]+([\-\.]{1}[a-z0-9]+)*\.[A-Za-z]{2,6}$/.test(value);
 
+/**
+ * Extracts all subdomains from a domain including itself.
+ * @param {string} domain The domain to be extracted.
+ * @returns {string[]}
+ */
+export const extractDomain = (domain) =>
+  domain.split(".").reduce((previous, current, index, array) => {
+    const nextIndex = index + 1;
+
+    if (nextIndex > array.length - 1) return previous;
+
+    const domain = [current, ...array.slice(nextIndex)].join(".");
+
+    previous.push(domain);
+
+    return previous;
+  }, []);
+
 /**
  * Checks if the value is a comment.
  * @param {string} value The value to be checked.