From 27f6e9f0d3a72d381e1bc752d0a7dceba27b4671 Mon Sep 17 00:00:00 2001
From: Viet Huynh <xa.lach@yahoo.com>
Date: Sun, 17 Sep 2023 19:55:43 +0700
Subject: [PATCH] added code comments

---
 cf_list_create.js | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/cf_list_create.js b/cf_list_create.js
index fb0e81b..3671642 100644
--- a/cf_list_create.js
+++ b/cf_list_create.js
@@ -55,22 +55,32 @@ await readFile(resolve(blocklistFilename), (line, rl) => {
 
   if (!_line) return;
 
+  // Check if the current line is a comment in any format
   if (isComment(_line)) return;
 
+  // Remove prefixes and suffixes in hosts, wildcard or adblock format
   const domain = normalizeDomain(_line);
 
+  // Check if it is a valid domain which is not a URL or does not contain
+  // characters like * in the middle of the domain
   if (!isValidDomain(domain)) return;
 
   processedDomainCount++;
 
+  // Get all the levels of the domain and check from the highest
+  // because we are blocking all subdomains
+  // Example: fourth.third.example.com => ["example.com", "third.example.com", "fourth.third.example.com"]
   const anyDomainExists = extractDomain(domain)
     .reverse()
     .some((item) => {
       if (blocklist.has(item)) {
         if (item === domain) {
+          // The exact domain is already blocked
           console.log(`Found ${item} in blocklist already - Skipping`);
           duplicateDomainCount++;
         } else {
+          // The higher-level domain is already blocked
+          // so it's not necessary to block this domain
           console.log(
             `Found ${item} in blocklist already - Skipping ${domain}`
           );