Issue 4878 - Start using ESLint for adblockpluscore

lib/filterClasses.js

Index: lib/filterClasses.js
diff --git a/lib/filterClasses.js b/lib/filterClasses.js
index 8ef7869d34c8bc4cefc54f54854d3264ef64ac35..f637e6afe687c0022f6847aa520470dda7adbf75 100644
--- a/lib/filterClasses.js
+++ b/lib/filterClasses.js
@@ -15,18 +15,20 @@
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+"use strict";
+
 /**
  * @fileOverview Definition of Filter class and its subclasses.
  */
 
-let {FilterNotifier} = require("filterNotifier");
-let {extend} = require("coreUtils");
-let {filterToRegExp} = require("common");
+const {FilterNotifier} = require("filterNotifier");
+const {extend} = require("coreUtils");
+const {filterToRegExp} = require("common");
 
 /**
  * Abstract base class for filters
  *
- * @param {String} text   string representation of the filter
+ * @param {string} text   string representation of the filter
  * @constructor
  */
 function Filter(text)
@@ -40,19 +42,19 @@ Filter.prototype =
 {
   /**
    * String representation of the filter
-   * @type String
+   * @type {string}
    */
   text: null,
 
   /**
    * Filter subscriptions the filter belongs to
-   * @type Subscription[]
+   * @type {Subscription[]}
    */
   subscriptions: null,
 
   /**
    * Filter type as a string, e.g. "blocking".
-   * @type String
+   * @type {string}
    */
   get type()
   {
@@ -63,13 +65,13 @@ Filter.prototype =
    * Serializes the filter to an array of strings for writing out on the disk.
    * @param {string[]} buffer  buffer to push the serialization results into
    */
-  serialize: function(buffer)
+  serialize(buffer)
   {
     buffer.push("[Filter]");
     buffer.push("text=" + this.text);
   },
 
-  toString: function()
+  toString()
   {
     return this.text;
   }
@@ -77,31 +79,31 @@ Filter.prototype =
 
 /**
  * Cache for known filters, maps string representation to filter objects.
- * @type Object
+ * @type {Object}
  */
 Filter.knownFilters = Object.create(null);
 
 /**
  * Regular expression that element hiding filters should match
- * @type RegExp
+ * @type {RegExp}
  */
-Filter.elemhideRegExp = /^([^\/\*\|\@"!]*?)#(\@)?(?:([\w\-]+|\*)((?:\([\w\-]+(?:[$^*]?=[^\(\)"]*)?\))*)|#(.+))$/;
+Filter.elemhideRegExp = /^([^/*|@"!]*?)#(@)?(?:([\w-]+|\*)((?:\([\w-]+(?:[$^*]?=[^()"]*)?\))*)|#(.+))$/;
 /**
  * Regular expression that RegExp filters specified as RegExps should match
- * @type RegExp
+ * @type {RegExp}
  */
-Filter.regexpRegExp = /^(@@)?\/.*\/(?:\$~?[\w\-]+(?:=[^,\s]+)?(?:,~?[\w\-]+(?:=[^,\s]+)?)*)?$/;
+Filter.regexpRegExp = /^(@@)?\/.*\/(?:\$~?[\w-]+(?:=[^,\s]+)?(?:,~?[\w-]+(?:=[^,\s]+)?)*)?$/;
 /**
  * Regular expression that options on a RegExp filter should match
- * @type RegExp
+ * @type {RegExp}
  */
-Filter.optionsRegExp = /\$(~?[\w\-]+(?:=[^,\s]+)?(?:,~?[\w\-]+(?:=[^,\s]+)?)*)$/;
+Filter.optionsRegExp = /\$(~?[\w-]+(?:=[^,\s]+)?(?:,~?[\w-]+(?:=[^,\s]+)?)*)$/;
 
 /**
- * Creates a filter of correct type from its text representation - does the basic parsing and
- * calls the right constructor then.
+ * Creates a filter of correct type from its text representation -
+ * does the basic parsing and calls the right constructor then.
  *
- * @param {String} text   as in Filter()
+ * @param {string} text   as in Filter()
  * @return {Filter}
  */
 Filter.fromText = function(text)
@@ -110,9 +112,13 @@ Filter.fromText = function(text)
     return Filter.knownFilters[text];
 
   let ret;
-  let match = (text.indexOf("#") >= 0 ? Filter.elemhideRegExp.exec(text) : null);
+  let match = (text.includes("#") ? Filter.elemhideRegExp.exec(text) : null);
   if (match)
-    ret = ElemHideBase.fromText(text, match[1], !!match[2], match[3], match[4], match[5]);
+  {
+    ret = ElemHideBase.fromText(
+      text, match[1], !!match[2], match[3], match[4], match[5]
+    );
+  }
   else if (text[0] == "!")
     ret = new CommentFilter(text);
   else
@@ -136,9 +142,9 @@ Filter.fromObject = function(obj)
     if ("disabled" in obj)
       ret._disabled = (obj.disabled == "true");
     if ("hitCount" in obj)
-      ret._hitCount = parseInt(obj.hitCount) || 0;
+      ret._hitCount = parseInt(obj.hitCount, 10) || 0;
     if ("lastHit" in obj)
-      ret._lastHit = parseInt(obj.lastHit) || 0;
+      ret._lastHit = parseInt(obj.lastHit, 10) || 0;
   }
   return ret;
 };
@@ -146,8 +152,10 @@ Filter.fromObject = function(obj)
 /**
  * Removes unnecessary whitespaces from filter text, will only return null if
  * the input parameter is null.
+ * @param {string} text
+ * @return {string}
  */
-Filter.normalize = function(/**String*/ text) /**String*/
+Filter.normalize = function(text)
 {
   if (!text)
     return text;
@@ -162,12 +170,12 @@ Filter.normalize = function(/**String*/ text) /**String*/
   }
   else if (Filter.elemhideRegExp.test(text))
   {
-    // Special treatment for element hiding filters, right side is allowed to contain spaces
-    let [, domain, separator, selector] = /^(.*?)(#\@?#?)(.*)$/.exec(text);
+    // Special treatment for element hiding filters, right side is
+    // allowed to contain spaces
+    let [, domain, separator, selector] = /^(.*?)(#@?#?)(.*)$/.exec(text);
     return domain.replace(/\s/g, "") + separator + selector.trim();
   }
-  else
-    return text.replace(/\s/g, "");
+  return text.replace(/\s/g, "");
 };
 
 /**
@@ -177,8 +185,8 @@ Filter.toRegExp = filterToRegExp;
 
 /**
  * Class for invalid filters
- * @param {String} text see Filter()
- * @param {String} reason Reason why this filter is invalid
+ * @param {string} text see Filter()
+ * @param {string} reason Reason why this filter is invalid
  * @constructor
  * @augments Filter
  */
@@ -195,19 +203,20 @@ InvalidFilter.prototype = extend(Filter, {
 
   /**
    * Reason why this filter is invalid
-   * @type String
+   * @type {string}
    */
   reason: null,
 
   /**
    * See Filter.serialize()
+   * @param {string[]} buffer  buffer to push the serialization results into
    */
-  serialize: function(buffer) {}
+  serialize(buffer) {}
 });
 
 /**
  * Class for comments
- * @param {String} text see Filter()
+ * @param {string} text see Filter()
  * @constructor
  * @augments Filter
  */
@@ -222,14 +231,16 @@ CommentFilter.prototype = extend(Filter, {
 
   /**
    * See Filter.serialize()
+   * @param {string[]} buffer  buffer to push the serialization results into
    */
-  serialize: function(buffer) {}
+  serialize(buffer) {}
 });
 
 /**
  * Abstract base class for filters that can get hits
- * @param {String} text see Filter()
- * @param {String} [domains] Domains that the filter is restricted to separated by domainSeparator e.g. "foo.com|bar.com|~baz.com"
+ * @param {string} text see Filter()
+ * @param {string} [domains] Domains that the filter is restricted to
+ *                  separated by domainSeparator e.g. "foo.com|bar.com|~baz.com"
  * @constructor
  * @augments Filter
  */
@@ -248,7 +259,7 @@ ActiveFilter.prototype = extend(Filter, {
 
   /**
    * Defines whether the filter is disabled
-   * @type Boolean
+   * @type {boolean}
    */
   get disabled()
   {
@@ -267,7 +278,7 @@ ActiveFilter.prototype = extend(Filter, {
 
   /**
    * Number of hits on the filter since the last reset
-   * @type Number
+   * @type {number}
    */
   get hitCount()
   {
@@ -285,8 +296,9 @@ ActiveFilter.prototype = extend(Filter, {
   },
 
   /**
-   * Last time the filter had a hit (in milliseconds since the beginning of the epoch)
-   * @type Number
+   * Last time the filter had a hit (in milliseconds since the
+   * beginning of the epoch)
+   * @type {number}
    */
   get lastHit()
   {
@@ -305,33 +317,35 @@ ActiveFilter.prototype = extend(Filter, {
 
   /**
    * String that the domains property should be generated from
-   * @type String
+   * @type {string}
    */
   domainSource: null,
 
   /**
-   * Separator character used in domainSource property, must be overridden by subclasses
-   * @type String
+   * Separator character used in domainSource property, must be
+   * overridden by subclasses
+   * @type {string}
    */
   domainSeparator: null,
 
   /**
    * Determines whether the trailing dot in domain names isn't important and
    * should be ignored, must be overridden by subclasses.
-   * @type Boolean
+   * @type {boolean}
    */
   ignoreTrailingDot: true,
 
   /**
    * Determines whether domainSource is already upper-case,
    * can be overridden by subclasses.
-   * @type Boolean
+   * @type {boolean}
    */
   domainSourceIsUpperCase: false,
 
   /**
-   * Map containing domains that this filter should match on/not match on or null if the filter should match on all domains
-   * @type Object
+   * Map containing domains that this filter should match on/not match
+   * on or null if the filter should match on all domains
+   * @type {Object}
    */
   get domains()
   {
@@ -346,7 +360,8 @@ ActiveFilter.prototype = extend(Filter, {
     if (this.domainSource)
     {
       let source = this.domainSource;
-      if (!this.domainSourceIsUpperCase) {
+      if (!this.domainSourceIsUpperCase)
+      {
         // RegExpFilter already have uppercase domains
         source = source.toUpperCase();
       }
@@ -401,28 +416,31 @@ ActiveFilter.prototype = extend(Filter, {
 
   /**
    * Array containing public keys of websites that this filter should apply to
-   * @type string[]
+   * @type {string[]}
    */
   sitekeys: null,
 
   /**
    * Checks whether this filter is active on a domain.
-   * @param {String} docDomain domain name of the document that loads the URL
-   * @param {String} [sitekey] public key provided by the document
-   * @return {Boolean} true in case of the filter being active
+   * @param {string} docDomain domain name of the document that loads the URL
+   * @param {string} [sitekey] public key provided by the document
+   * @return {boolean} true in case of the filter being active
    */
-  isActiveOnDomain: function(docDomain, sitekey)
+  isActiveOnDomain(docDomain, sitekey)
   {
-    // Sitekeys are case-sensitive so we shouldn't convert them to upper-case to avoid false
-    // positives here. Instead we need to change the way filter options are parsed.
-    if (this.sitekeys && (!sitekey || this.sitekeys.indexOf(sitekey.toUpperCase()) < 0))
+    // Sitekeys are case-sensitive so we shouldn't convert them to
+    // upper-case to avoid false positives here. Instead we need to
+    // change the way filter options are parsed.
+    if (this.sitekeys &&
+        (!sitekey || this.sitekeys.indexOf(sitekey.toUpperCase()) < 0))
       return false;
 
     // If no domains are set the rule matches everywhere
     if (!this.domains)
       return true;
 
-    // If the document has no host name, match only if the filter isn't restricted to specific domains
+    // If the document has no host name, match only if the filter
+    // isn't restricted to specific domains
     if (!docDomain)
       return this.domains[""];
 
@@ -445,8 +463,10 @@ ActiveFilter.prototype = extend(Filter, {
 
   /**
    * Checks whether this filter is active only on a domain and its subdomains.
+   * @param {string} docDomain
+   * @return {boolean}
    */
-  isActiveOnlyOnDomain: function(/**String*/ docDomain) /**Boolean*/
+  isActiveOnlyOnDomain(docDomain)
   {
     if (!docDomain || !this.domains || this.domains[""])
       return false;
@@ -456,16 +476,26 @@ ActiveFilter.prototype = extend(Filter, {
     docDomain = docDomain.toUpperCase();
 
     for (let domain in this.domains)
-      if (this.domains[domain] && domain != docDomain && (domain.length <= docDomain.length || domain.indexOf("." + docDomain) != domain.length - docDomain.length - 1))
-        return false;
+    {
+      if (this.domains[domain] && domain != docDomain)
+      {
+        if (domain.length <= docDomain.length)
+          return false;
+
+        let pos = domain.indexOf("." + docDomain);
+        if (pos != domain.length - docDomain.length - 1)
+          return false;
+      }
+    }
 
     return true;
   },
 
   /**
    * Checks whether this filter is generic or specific
+   * @return {boolean}
    */
-  isGeneric: function() /**Boolean*/
+  isGeneric()
   {
     return !(this.sitekeys && this.sitekeys.length) &&
             (!this.domains || this.domains[""]);
@@ -473,8 +503,9 @@ ActiveFilter.prototype = extend(Filter, {
 
   /**
    * See Filter.serialize()
+   * @param {string[]} buffer  buffer to push the serialization results into
    */
-  serialize: function(buffer)
+  serialize(buffer)
   {
     if (this._disabled || this._hitCount || this._lastHit)
     {
@@ -491,17 +522,24 @@ ActiveFilter.prototype = extend(Filter, {
 
 /**
  * Abstract base class for RegExp-based filters
- * @param {String} text see Filter()
- * @param {String} regexpSource filter part that the regular expression should be build from
- * @param {Number} [contentType] Content types the filter applies to, combination of values from RegExpFilter.typeMap
- * @param {Boolean} [matchCase] Defines whether the filter should distinguish between lower and upper case letters
- * @param {String} [domains] Domains that the filter is restricted to, e.g. "foo.com|bar.com|~baz.com"
- * @param {Boolean} [thirdParty] Defines whether the filter should apply to third-party or first-party content only
- * @param {String} [sitekeys] Public keys of websites that this filter should apply to
+ * @param {string} text see Filter()
+ * @param {string} regexpSource filter part that the regular expression should
+ *                              be build from
+ * @param {number} [contentType] Content types the filter applies to,
+ *                               combination of values from RegExpFilter.typeMap
+ * @param {boolean} [matchCase] Defines whether the filter should distinguish
+ *                              between lower and upper case letters
+ * @param {string} [domains] Domains that the filter is restricted to,
+ *                           e.g. "foo.com|bar.com|~baz.com"
+ * @param {boolean} [thirdParty] Defines whether the filter should apply to
+ *                               third-party or first-party content only
+ * @param {string} [sitekeys] Public keys of websites that this filter should
+ *                            apply to
  * @constructor
  * @augments ActiveFilter
  */
-function RegExpFilter(text, regexpSource, contentType, matchCase, domains, thirdParty, sitekeys)
+function RegExpFilter(text, regexpSource, contentType, matchCase, domains,
+                      thirdParty, sitekeys)
 {
   ActiveFilter.call(this, text, domains, sitekeys);
 
@@ -514,10 +552,14 @@ function RegExpFilter(text, regexpSource, contentType, matchCase, domains, third
   if (sitekeys != null)
     this.sitekeySource = sitekeys;
 
-  if (regexpSource.length >= 2 && regexpSource[0] == "/" && regexpSource[regexpSource.length - 1] == "/")
+  if (regexpSource.length >= 2 &&
+      regexpSource[0] == "/" &&
+      regexpSource[regexpSource.length - 1] == "/")
   {
-    // The filter is a regular expression - convert it immediately to catch syntax errors
-    let regexp = new RegExp(regexpSource.substr(1, regexpSource.length - 2), this.matchCase ? "" : "i");
+    // The filter is a regular expression - convert it immediately to
+    // catch syntax errors
+    let regexp = new RegExp(regexpSource.substr(1, regexpSource.length - 2),
+                            this.matchCase ? "" : "i");
     Object.defineProperty(this, "regexp", {value: regexp});
   }
   else
@@ -535,8 +577,9 @@ RegExpFilter.prototype = extend(ActiveFilter, {
   domainSourceIsUpperCase: true,
 
   /**
-   * Number of filters contained, will always be 1 (required to optimize Matcher).
-   * @type Integer
+   * Number of filters contained, will always be 1 (required to
+   * optimize Matcher).
+   * @type {number}
    */
   length: 1,
 
@@ -546,13 +589,14 @@ RegExpFilter.prototype = extend(ActiveFilter, {
   domainSeparator: "|",
 
   /**
-   * Expression from which a regular expression should be generated - for delayed creation of the regexp property
-   * @type String
+   * Expression from which a regular expression should be generated -
+   * for delayed creation of the regexp property
+   * @type {string}
    */
   regexpSource: null,
   /**
    * Regular expression to be used when testing against this filter
-   * @type RegExp
+   * @type {RegExp}
    */
   get regexp()
   {
@@ -568,30 +612,33 @@ RegExpFilter.prototype = extend(ActiveFilter, {
     return regexp;
   },
   /**
-   * Content types the filter applies to, combination of values from RegExpFilter.typeMap
-   * @type Number
+   * Content types the filter applies to, combination of values from
+   * RegExpFilter.typeMap
+   * @type {number}
    */
   contentType: 0x7FFFFFFF,
   /**
-   * Defines whether the filter should distinguish between lower and upper case letters
-   * @type Boolean
+   * Defines whether the filter should distinguish between lower and
+   * upper case letters
+   * @type {boolean}
    */
   matchCase: false,
   /**
-   * Defines whether the filter should apply to third-party or first-party content only. Can be null (apply to all content).
-   * @type Boolean
+   * Defines whether the filter should apply to third-party or
+   * first-party content only. Can be null (apply to all content).
+   * @type {boolean}
    */
   thirdParty: null,
 
   /**
    * String that the sitekey property should be generated from
-   * @type String
+   * @type {string}
    */
   sitekeySource: null,
 
   /**
    * Array containing public keys of websites that this filter should apply to
-   * @type string[]
+   * @type {string[]}
    */
   get sitekeys()
   {
@@ -609,41 +656,41 @@ RegExpFilter.prototype = extend(ActiveFilter, {
       this.sitekeySource = null;
     }
 
-    Object.defineProperty(this, "sitekeys", {value: sitekeys, enumerable: true});
+    Object.defineProperty(
+      this, "sitekeys", {value: sitekeys, enumerable: true}
+    );
     return this.sitekeys;
   },
 
   /**
    * Tests whether the URL matches this filter
-   * @param {String} location URL to be tested
+   * @param {string} location URL to be tested
    * @param {number} typeMask bitmask of content / request types to match
-   * @param {String} docDomain domain name of the document that loads the URL
-   * @param {Boolean} thirdParty should be true if the URL is a third-party request
-   * @param {String} sitekey public key provided by the document
-   * @return {Boolean} true in case of a match
+   * @param {string} docDomain domain name of the document that loads the URL
+   * @param {boolean} thirdParty should be true if the URL is a third-party
+   *                             request
+   * @param {string} sitekey public key provided by the document
+   * @return {boolean} true in case of a match
    */
-  matches: function(location, typeMask, docDomain, thirdParty, sitekey)
+  matches(location, typeMask, docDomain, thirdParty, sitekey)
   {
     if (this.contentType & typeMask &&
         (this.thirdParty == null || this.thirdParty == thirdParty) &&
         this.isActiveOnDomain(docDomain, sitekey) && this.regexp.test(location))
-    {
       return true;
-    }
-
     return false;
   }
 });
 
 // Required to optimize Matcher, see also RegExpFilter.prototype.length
-Object.defineProperty(RegExpFilter.prototype, "0",
-{
-  get: function() { return this; }
+Object.defineProperty(RegExpFilter.prototype, "0", {
+  get() { return this; }
 });
 
 /**
  * Creates a RegExp filter from its text representation
- * @param {String} text   same as in Filter()
+ * @param {string} text   same as in Filter()
+ * @return {RegExpFilter}
  */
 RegExpFilter.fromText = function(text)
 {
@@ -686,7 +733,7 @@ RegExpFilter.fromText = function(text)
       else if (option[0] == "~" && option.substr(1) in RegExpFilter.typeMap)
       {
         if (contentType == null)
-          contentType = RegExpFilter.prototype.contentType;
+          ({contentType} = RegExpFilter.prototype);
         contentType &= ~RegExpFilter.typeMap[option.substr(1)];
       }
       else if (option == "MATCH_CASE")
@@ -713,9 +760,12 @@ RegExpFilter.fromText = function(text)
   try
   {
     if (blocking)
-      return new BlockingFilter(origText, text, contentType, matchCase, domains, thirdParty, sitekeys, collapse);
-    else
-      return new WhitelistFilter(origText, text, contentType, matchCase, domains, thirdParty, sitekeys);
+    {
+      return new BlockingFilter(origText, text, contentType, matchCase, domains,
+                                thirdParty, sitekeys, collapse);
+    }
+    return new WhitelistFilter(origText, text, contentType, matchCase, domains,
+                               thirdParty, sitekeys);
   }
   catch (e)
   {
@@ -761,20 +811,23 @@ RegExpFilter.prototype.contentType &= ~(RegExpFilter.typeMap.DOCUMENT |
 
 /**
  * Class for blocking filters
- * @param {String} text see Filter()
- * @param {String} regexpSource see RegExpFilter()
- * @param {Number} contentType see RegExpFilter()
- * @param {Boolean} matchCase see RegExpFilter()
- * @param {String} domains see RegExpFilter()
- * @param {Boolean} thirdParty see RegExpFilter()
- * @param {String} sitekeys see RegExpFilter()
- * @param {Boolean} collapse  defines whether the filter should collapse blocked content, can be null
+ * @param {string} text see Filter()
+ * @param {string} regexpSource see RegExpFilter()
+ * @param {number} contentType see RegExpFilter()
+ * @param {boolean} matchCase see RegExpFilter()
+ * @param {string} domains see RegExpFilter()
+ * @param {boolean} thirdParty see RegExpFilter()
+ * @param {string} sitekeys see RegExpFilter()
+ * @param {boolean} collapse  defines whether the filter should collapse blocked
+ *                            content, can be null
  * @constructor
  * @augments RegExpFilter
  */
-function BlockingFilter(text, regexpSource, contentType, matchCase, domains, thirdParty, sitekeys, collapse)
+function BlockingFilter(text, regexpSource, contentType, matchCase, domains,
+                        thirdParty, sitekeys, collapse)
 {
-  RegExpFilter.call(this, text, regexpSource, contentType, matchCase, domains, thirdParty, sitekeys);
+  RegExpFilter.call(this, text, regexpSource, contentType, matchCase, domains,
+                    thirdParty, sitekeys);
 
   this.collapse = collapse;
 }
@@ -784,27 +837,30 @@ BlockingFilter.prototype = extend(RegExpFilter, {
   type: "blocking",
 
   /**
-   * Defines whether the filter should collapse blocked content. Can be null (use the global preference).
-   * @type Boolean
+   * Defines whether the filter should collapse blocked content.
+   * Can be null (use the global preference).
+   * @type {boolean}
    */
   collapse: null
 });
 
 /**
  * Class for whitelist filters
- * @param {String} text see Filter()
- * @param {String} regexpSource see RegExpFilter()
- * @param {Number} contentType see RegExpFilter()
- * @param {Boolean} matchCase see RegExpFilter()
- * @param {String} domains see RegExpFilter()
- * @param {Boolean} thirdParty see RegExpFilter()
- * @param {String} sitekeys see RegExpFilter()
+ * @param {string} text see Filter()
+ * @param {string} regexpSource see RegExpFilter()
+ * @param {number} contentType see RegExpFilter()
+ * @param {boolean} matchCase see RegExpFilter()
+ * @param {string} domains see RegExpFilter()
+ * @param {boolean} thirdParty see RegExpFilter()
+ * @param {string} sitekeys see RegExpFilter()
  * @constructor
  * @augments RegExpFilter
  */
-function WhitelistFilter(text, regexpSource, contentType, matchCase, domains, thirdParty, sitekeys)
+function WhitelistFilter(text, regexpSource, contentType, matchCase, domains,
+                         thirdParty, sitekeys)
 {
-  RegExpFilter.call(this, text, regexpSource, contentType, matchCase, domains, thirdParty, sitekeys);
+  RegExpFilter.call(this, text, regexpSource, contentType, matchCase, domains,
+                    thirdParty, sitekeys);
 }
 exports.WhitelistFilter = WhitelistFilter;
 
@@ -814,9 +870,11 @@ WhitelistFilter.prototype = extend(RegExpFilter, {
 
 /**
  * Base class for element hiding filters
- * @param {String} text see Filter()
- * @param {String} [domains] Host names or domains the filter should be restricted to
- * @param {String} selector   CSS selector for the HTML elements that should be hidden
+ * @param {string} text see Filter()
+ * @param {string} [domains] Host names or domains the filter should be
+ *                           restricted to
+ * @param {string} selector   CSS selector for the HTML elements that should be
+ *                            hidden
  * @constructor
  * @augments ActiveFilter
  */
@@ -825,7 +883,10 @@ function ElemHideBase(text, domains, selector)
   ActiveFilter.call(this, text, domains || null);
 
   if (domains)
-    this.selectorDomain = domains.replace(/,~[^,]+/g, "").replace(/^~[^,]+,?/, "").toLowerCase();
+  {
+    this.selectorDomain = domains.replace(/,~[^,]+/g, "")
+                                 .replace(/^~[^,]+,?/, "").toLowerCase();
+  }
 
   // Braces are being escaped to prevent CSS rule injection.
   this.selector = selector.replace("{", "\\x7B ").replace("}", "\\x7D ");
@@ -844,13 +905,14 @@ ElemHideBase.prototype = extend(ActiveFilter, {
   ignoreTrailingDot: false,
 
   /**
-   * Host name or domain the filter should be restricted to (can be null for no restriction)
-   * @type String
+   * Host name or domain the filter should be restricted to (can be null for
+   * no restriction)
+   * @type {string}
    */
   selectorDomain: null,
   /**
    * CSS selector for the HTML elements that should be hidden
-   * @type String
+   * @type {string}
    */
   selector: null
 });
@@ -858,15 +920,18 @@ ElemHideBase.prototype = extend(ActiveFilter, {
 /**
  * Creates an element hiding filter from a pre-parsed text representation
  *
- * @param {String} text         same as in Filter()
- * @param {String} domain       domain part of the text representation (can be empty)
- * @param {Boolean} isException exception rule indicator
- * @param {String} tagName      tag name part (can be empty)
- * @param {String} attrRules    attribute matching rules (can be empty)
- * @param {String} selector     raw CSS selector (can be empty)
- * @return {ElemHideFilter|ElemHideException|ElemHideEmulationFilter|InvalidFilter}
+ * @param {string} text         same as in Filter()
+ * @param {string} domain       domain part of the text representation
+ *                              (can be empty)
+ * @param {boolean} isException exception rule indicator
+ * @param {string} tagName      tag name part (can be empty)
+ * @param {string} attrRules    attribute matching rules (can be empty)
+ * @param {string} selector     raw CSS selector (can be empty)
+ * @return {ElemHideFilter|ElemHideException|
+ *          ElemHideEmulationFilter|InvalidFilter}
  */
-ElemHideBase.fromText = function(text, domain, isException, tagName, attrRules, selector)
+ElemHideBase.fromText = function(text, domain, isException, tagName, attrRules,
+                                 selector)
 {
   if (!selector)
   {
@@ -877,7 +942,7 @@ ElemHideBase.fromText = function(text, domain, isException, tagName, attrRules,
     let additional = "";
     if (attrRules)
     {
-      attrRules = attrRules.match(/\([\w\-]+(?:[$^*]?=[^\(\)"]*)?\)/g);
+      attrRules = attrRules.match(/\([\w-]+(?:[$^*]?=[^()"]*)?\)/g);
       for (let rule of attrRules)
       {
         rule = rule.substr(1, rule.length - 2);
@@ -898,7 +963,7 @@ ElemHideBase.fromText = function(text, domain, isException, tagName, attrRules,
     }
 
     if (id)
-      selector = tagName + "." + id + additional + "," + tagName + "#" + id + additional;
+      selector = `${tagName}.${id}${additional},${tagName}#${id}${additional}`;
     else if (tagName || additional)
       selector = tagName + additional;
     else
@@ -929,9 +994,9 @@ ElemHideBase.fromText = function(text, domain, isException, tagName, attrRules,
 
 /**
  * Class for element hiding filters
- * @param {String} text see Filter()
- * @param {String} domains  see ElemHideBase()
- * @param {String} selector see ElemHideBase()
+ * @param {string} text see Filter()
+ * @param {string} domains  see ElemHideBase()
+ * @param {string} selector see ElemHideBase()
  * @constructor
  * @augments ElemHideBase
  */
@@ -947,9 +1012,9 @@ ElemHideFilter.prototype = extend(ElemHideBase, {
 
 /**
  * Class for element hiding exceptions
- * @param {String} text see Filter()
- * @param {String} domains  see ElemHideBase()
- * @param {String} selector see ElemHideBase()
+ * @param {string} text see Filter()
+ * @param {string} domains  see ElemHideBase()
+ * @param {string} selector see ElemHideBase()
  * @constructor
  * @augments ElemHideBase
  */
@@ -965,9 +1030,9 @@ ElemHideException.prototype = extend(ElemHideBase, {
 
 /**
  * Class for element hiding emulation filters
- * @param {String} text           see Filter()
- * @param {String} domains        see ElemHideBase()
- * @param {String} selector       see ElemHideBase()
+ * @param {string} text           see Filter()
+ * @param {string} domains        see ElemHideBase()
+ * @param {string} selector       see ElemHideBase()
  * @constructor
  * @augments ElemHideBase
  */