Issue 6559 - Use maps and sets where appropriate

lib/elemHide.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 "use strict";
 
 /**
  * @fileOverview Element hiding implementation.
  */
 
 const {ElemHideException} = require("./filterClasses");
 const {FilterNotifier} = require("./filterNotifier");
 
 /**
  * Lookup table, filters by their associated key
  * @type {Filter[]}

[Manish Jethani, 2018/04/06 12:44:09]

I've updated some of the types here.

  */
 let filterByKey = [];
 
 /**
  * Lookup table, keys of the filters by filter
  * @type {Map.<Filter,number>}

[Manish Jethani, 2018/04/06 12:44:09]

The key is in fact a number.

  */
 let keyByFilter = new Map();
 
 /**
  * Nested lookup table, filter (or false if inactive) by filter key by domain.
  * (Only contains filters that aren't unconditionally matched for all domains.)
  * @type {Map.<string,Map.<number,(Filter|boolean)>>}
  */
 let filtersByDomain = new Map();
 
@@ skipping 243 matching lines @@
   },
 
   /**
    * Returns a list of filter keys for selectors which apply to all websites
    * without exception.
    * @returns {number[]}
    */
   getUnconditionalFilterKeys()
   {
     if (!unconditionalFilterKeys)
-      unconditionalFilterKeys = [...filterKeyBySelector.values()];
+    {
+      let selectors = this.getUnconditionalSelectors();
+      unconditionalFilterKeys = [];
+      for (let selector of selectors)
+        unconditionalFilterKeys.push(filterKeyBySelector.get(selector));
+    }
     return unconditionalFilterKeys.slice();
   },
 
 
   /**
    * Constant used by getSelectorsForDomain to return all selectors applying to
    * a particular hostname.
    */
   ALL_MATCHING: 0,
 
@@ skipping 69 matching lines @@
 
       let nextDot = currentDomain.indexOf(".");
       currentDomain = nextDot == -1 ? "" : currentDomain.substr(nextDot + 1);
     }
 
     if (provideFilterKeys)
       return [selectors, filterKeys];
     return selectors;
   }
 };