Improve code readability with section separators

Added clear visual section separators to all library files for better code
navigation and readability:

lib/main.js:
- Dependencies
- Configuration
- Cache Configuration
- Helper Functions
- IPv4 Lookup Function
- IPv6 Lookup Function
- IPv4-Mapped IPv6 Handler
- Data Loading Functions (IPv4 and IPv6)
- Public API
- Initialize

lib/utils.js:
- IPv4 Conversion Functions (aton4, ntoa4)
- IPv6 Conversion Functions (aton6, ntoa6)
- Comparison Functions (cmp, cmp6)
- IP Address Validation (isPrivateIP)

lib/fsWatcher.js:
- Watcher Management
- File System Watch with Debounce
- Exports

Benefits:
- Easier code navigation
- Clear logical separation of concerns
- Better developer experience
- Maintains all functionality and performance

All 94 tests pass successfully.

Author: claude

dist/utils.js

@@ -1,13 +1,25 @@
+// ============================================================================
+// File System Watcher for Auto-Reloading GeoIP Data
+// ============================================================================
+
 const { access, constants, watch } = require('node:fs');
 const { join } = require('node:path');
 const FSWatcher = {};
 
+// ============================================================================
+// Watcher Management
+// ============================================================================
+
 /**
  * Takes an FSWatcher object and closes it.
  * @param {string} name - The name of the watcher to close.
  */
 const stopWatching = name => FSWatcher[name].close();
 
+// ============================================================================
+// File System Watch with Debounce
+// ============================================================================
+
 /**
  * Takes a directory/file and watch for change. Upon change, call the callback.
  *
@@ -66,4 +78,8 @@ const makeFsWatchFilter = (name, directory, filename, cdDelay, callback) => {
 	FSWatcher[name] = watch(directory, onWatchEvent);
 };
 
+// ============================================================================
+// Exports
+// ============================================================================
+
 module.exports = { makeFsWatchFilter, stopWatching };

lib/fsWatcher.js

@@ -1,3 +1,7 @@
+// ============================================================================
+// Dependencies
+// ============================================================================
+
 const { open, fstat, read, close, openSync, fstatSync, readSync, closeSync } = require('node:fs');
 const { join, resolve } = require('node:path');
 const { isIP } = require('node:net');
@@ -6,6 +10,10 @@ const { aton4, aton6, cmp6, ntoa4, ntoa6, cmp } = require('./utils.js');
 const fsWatcher = require('./fsWatcher.js');
 const { version } = require('../package.json');
 
+// ============================================================================
+// Configuration
+// ============================================================================
+
 const watcherName = 'dataWatcher';
 
 const geoDataDir = resolve(
@@ -27,6 +35,10 @@ const privateRange4 = [
 	[aton4('192.168.0.0'), aton4('192.168.255.255')],
 ];
 
+// ============================================================================
+// Cache Configuration
+// ============================================================================
+
 const conf4 = {
 	firstIP: null,
 	lastIP: null,
@@ -45,20 +57,21 @@ const conf6 = {
 	recordSize: 48,
 };
 
-// Copy original configs
 let cache4 = { ...conf4 };
 let cache6 = { ...conf6 };
 
 const RECORD_SIZE = 10;
 const RECORD_SIZE6 = 34;
 
-// Helper function to remove null terminators
+// ============================================================================
+// Helper Functions
+// ============================================================================
+
 const removeNullTerminator = str => {
 	const nullIndex = str.indexOf('\0');
 	return nullIndex === -1 ? str : str.substring(0, nullIndex);
 };
 
-// Helper function to read IPv6 addresses from buffer
 const readIp6 = (buffer, line, recordSize, offset) => {
 	const ipArray = [];
 	for (let i = 0; i < 2; i++) {
@@ -67,6 +80,10 @@ const readIp6 = (buffer, line, recordSize, offset) => {
 	return ipArray;
 };
 
+// ============================================================================
+// IPv4 Lookup Function
+// ============================================================================
+
 const lookup4 = ip => {
 	let fline = 0;
 	let cline = cache4.lastLine;
@@ -146,6 +163,10 @@ const lookup4 = ip => {
 	}
 };
 
+// ============================================================================
+// IPv6 Lookup Function
+// ============================================================================
+
 const lookup6 = ip => {
 	const buffer = cache6.mainBuffer;
 	const recordSize = cache6.recordSize;
@@ -206,6 +227,10 @@ const lookup6 = ip => {
 	}
 };
 
+// ============================================================================
+// IPv4-Mapped IPv6 Handler
+// ============================================================================
+
 const V6_PREFIX_1 = '0:0:0:0:0:FFFF:';
 const V6_PREFIX_2 = '::FFFF:';
 const get4mapped = ip => {
@@ -215,6 +240,10 @@ const get4mapped = ip => {
 	return null;
 };
 
+// ============================================================================
+// Data Loading Functions - IPv4
+// ============================================================================
+
 function preload(callback) {
 	let datFile;
 	let datSize;
@@ -337,6 +366,10 @@ function preload(callback) {
 	}
 }
 
+// ============================================================================
+// Data Loading Functions - IPv6
+// ============================================================================
+
 function preload6(callback) {
 	let datFile;
 	let datSize;
@@ -433,6 +466,10 @@ function preload6(callback) {
 	}
 }
 
+// ============================================================================
+// Public API
+// ============================================================================
+
 module.exports = {
 	cmp,
 
@@ -513,6 +550,10 @@ module.exports = {
 	version,
 };
 
+// ============================================================================
+// Initialize - Load data on module startup
+// ============================================================================
+
 preload();
 preload6();
 

lib/main.js

@@ -1,10 +1,26 @@
+// ============================================================================
+// Utility Functions for IP Address Conversion and Comparison
+// ============================================================================
+
 const utils = module.exports = {};
 
+// ============================================================================
+// IPv4 Conversion Functions
+// ============================================================================
+
 utils.aton4 = a => {
 	const parts = a.split('.');
 	return ((parseInt(parts[0], 10) << 24) >>> 0) + ((parseInt(parts[1], 10) << 16) >>> 0) + ((parseInt(parts[2], 10) << 8) >>> 0) + (parseInt(parts[3], 10) >>> 0);
 };
 
+utils.ntoa4 = n => {
+	return ((n >>> 24) & 0xff) + '.' + ((n >>> 16) & 0xff) + '.' + ((n >>> 8) & 0xff) + '.' + (n & 0xff);
+};
+
+// ============================================================================
+// IPv6 Conversion Functions
+// ============================================================================
+
 utils.aton6 = a => {
 	a = a.replace(/"/g, '').split(':');
 
@@ -39,6 +55,21 @@ utils.aton6 = a => {
 	return r;
 };
 
+utils.ntoa6 = n => {
+	let a = '[';
+
+	for (let i = 0; i < n.length; i++) {
+		a += (n[i] >>> 16).toString(16) + ':';
+		a += (n[i] & 0xffff).toString(16) + ':';
+	}
+
+	a = a.replace(/:$/, ']').replace(/:0+/g, ':').replace(/::+/, '::');
+	return a;
+};
+
+// ============================================================================
+// Comparison Functions
+// ============================================================================
 
 utils.cmp = (a, b) => {
 	if (typeof a === 'number' && typeof b === 'number') return (a < b ? -1 : (a > b ? 1 : 0));
@@ -56,6 +87,10 @@ utils.cmp6 = (a, b) => {
 	return 0;
 };
 
+// ============================================================================
+// IP Address Validation
+// ============================================================================
+
 utils.isPrivateIP = addr => {
 	const str = addr.toString();
 	return str.startsWith('10.') ||
@@ -65,20 +100,4 @@ utils.isPrivateIP = addr => {
 		str.startsWith('169.254.') ||
 		str.startsWith('fc00:') ||
 		str.startsWith('fe80:');
-};
-
-utils.ntoa4 = n => {
-	return ((n >>> 24) & 0xff) + '.' + ((n >>> 16) & 0xff) + '.' + ((n >>> 8) & 0xff) + '.' + (n & 0xff);
-};
-
-utils.ntoa6 = n => {
-	let a = '[';
-
-	for (let i = 0; i < n.length; i++) {
-		a += (n[i] >>> 16).toString(16) + ':';
-		a += (n[i] & 0xffff).toString(16) + ':';
-	}
-
-	a = a.replace(/:$/, ']').replace(/:0+/g, ':').replace(/::+/, '::');
-	return a;
 };