Clean-up and add a few more comments

index.js

@@ -99,7 +99,6 @@ function factory(options) {
 
   return {
     extractHostname: _extractHostname,
-    isIp: isIp,
     isValid: isValid,
     parse: parse,
     tldExists: function (url) {

lib/clean-host.js

@@ -20,15 +20,24 @@ var isValid = require('./is-valid.js');
 var hasPrefixRE = /^(([a-z][a-z0-9+.-]*)?:)?\/\//;
 
 
-// @see https://github.com/oncletom/tld.js/issues/95
-function rtrim(value) {
+/**
+ * @see https://github.com/oncletom/tld.js/issues/95
+ *
+ * @param {string} value
+ */
+function trimTrailingDots(value) {
   if (value[value.length - 1] === '.') {
     return value.substr(0, value.length - 1);
   }
   return value;
 }
 
 
+/**
+ * Fast check to avoid calling `trim` when not needed.
+ *
+ * @param {string} value
+ */
 function checkTrimmingNeeded(value) {
   return (
     value.length > 0 && (
@@ -39,6 +48,11 @@ function checkTrimmingNeeded(value) {
 }
 
 
+/**
+ * Fast check to avoid calling `toLowerCase` when not needed.
+ *
+ * @param {string} value
+ */
 function checkLowerCaseNeeded(value) {
   for (var i = 0; i < value.length; i += 1) {
     var code = value.charCodeAt(i);
@@ -54,7 +68,7 @@ function checkLowerCaseNeeded(value) {
 module.exports = function extractHostname(value) {
   // First check if `value` is already a valid hostname.
   if (isValid(value)) {
-    return rtrim(value);
+    return trimTrailingDots(value);
   }
 
   var url = value;
@@ -75,7 +89,7 @@ module.exports = function extractHostname(value) {
 
   // Try again after `url` has been transformed to lowercase and trimmed.
   if ((needsLowerCase || needsTrimming) && isValid(url)) {
-    return rtrim(url);
+    return trimTrailingDots(url);
   }
 
   // Proceed with heavier url parsing to extract the hostname.
@@ -86,7 +100,7 @@ module.exports = function extractHostname(value) {
   var parts = URL.parse(url, null, true);
 
   if (parts.hostname) {
-    return rtrim(parts.hostname);
+    return trimTrailingDots(parts.hostname);
   }
 
   return null;

lib/is-valid.js

@@ -28,8 +28,8 @@ function isAlpha(code) {
 
 
 /**
- * Check if a hostname string is valid (according to RFC
- * It's usually a preliminary check before trying to use getDomain or anything else
+ * Check if a hostname string is valid (according to RFC). It's usually a
+ * preliminary check before trying to use getDomain or anything else.
  *
  * Beware: it does not check if the TLD exists.
  *