Issue 4795 - Use modern JavaScript syntax

lib/filterValidation.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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/>.
  */
 
 /** @module filterValidation */
 
+"use strict";
+
 let {Filter, InvalidFilter, ElemHideBase} = require("filterClasses");
 let {Utils} = require("utils");
 
 /**
  * An error returned by
  * {@link module:filterValidation.parseFilter parseFilter()} or
  * {@link module:filterValidation.parseFilters parseFilters()}
  * indicating that a given filter cannot be parsed,
  * contains an invalid CSS selector or is a filter list header.
  *
@@ skipping 26 matching lines @@
    *
    * @type {?number}
    */
   lineno: null,
 
   /**
    * Returns a detailed translated error message.
    *
    * @return {string}
    */
-  toString: function()
+  toString()
   {
     let message;
     if (this.reason)
       message = Utils.getString(this.reason);
     else
       message = ext.i18n.getMessage(
         this.type.replace(/-/g, "_"),
         "selector" in this ? "'" + this.selector + "'" : null
       );
 
@@ skipping 31 matching lines @@
  *
  */
 
 let parseFilter =
 /**
  * Parses and validates a filter given by the user.
  *
  * @param {string}  text
  * @return {ParsedFilter}
  */
-exports.parseFilter = function(text)
+exports.parseFilter = text =>
 {
   let filter = null;
   text = Filter.normalize(text);
 
   if (text)
   {
     if (text[0] == "[")
       return {error: new FilterParsingError("unexpected-filter-list-header")};
 
     filter = Filter.fromText(text);
@@ skipping 13 matching lines @@
  * @property {Filter[]} filters  The parsed result without invalid filters.
  * @property {FilterParsingError[]} errors  See {@link module:filterValidation~FilterParsingError FilterParsingError}
  */
 
 /**
  * Parses and validates a newline-separated list of filters given by the user.
  *
  * @param {string}  text
  * @return {ParsedFilters}
  */
-exports.parseFilters = function(text)
+exports.parseFilters = text =>
 {
   let lines = text.split("\n");
   let filters = [];
   let errors = [];
 
   for (let i = 0; i < lines.length; i++)
   {
     let {filter, error} = parseFilter(lines[i]);
 
     if (filter)
       filters.push(filter);
 
     if (error)
     {
       error.lineno = i + 1;
       errors.push(error);
     }
   }
 
   return {filters: filters, errors: errors};
 };