Issue 4864 - Start using ESLint for adblockpluschrome

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
@@ skipping 11 matching lines @@
 const {Filter, InvalidFilter, ElemHideBase} = require("filterClasses");
 const {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.
  *
+ * @param {string} type See documentation in the constructor below.
+ * @param {Object} [details] Contains the "reason" and / or "selector"
+ *                           properties.
  * @constructor
  */
 function FilterParsingError(type, details)
 {
   /**
    * Indicates why the filter is rejected. Possible choices:
    * "invalid-filter", "invalid-css-selector", "unexpected-filter-list-header"
    *
    * @type {string}
    */
@@ skipping 20 matching lines @@
 
   /**
    * Returns a detailed translated error message.
    *
    * @return {string}
    */
   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
       );
+    }
 
     if (this.lineno)
-      message = ext.i18n.getMessage("line", this.lineno.toLocaleString()) + ": " + message;
-
+    {
+      message = ext.i18n.getMessage(
+        "line", this.lineno.toLocaleString()
+      ) + ": " + message;
+    }
     return message;
   }
 };
 
 function isValidCSSSelector(selector)
 {
   let style = document.createElement("style");
   document.documentElement.appendChild(style);
-  let sheet = style.sheet;
+  let {sheet} = style;
   document.documentElement.removeChild(style);
 
   try
   {
     document.querySelector(selector);
     sheet.insertRule(selector + "{}", 0);
   }
   catch (e)
   {
     return false;
   }
   return true;
 }
 
 /**
  * @typedef ParsedFilter
  * @property {?Filter} [filter]  The parsed filter if it is valid.
  *                               Or null if the given string is empty.
- * @property {FilterParsingError} [error]  See {@link module:filterValidation~FilterParsingError FilterParsingError}
- *
+ * @property {FilterParsingError} [error]
+ * See {@link module:filterValidation~FilterParsingError FilterParsingError}
  */
 
 let parseFilter =
 /**
  * Parses and validates a filter given by the user.
  *
  * @param {string}  text
  * @return {ParsedFilter}
  */
 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);
 
     if (filter instanceof InvalidFilter)
-      return {error: new FilterParsingError("invalid-filter", {reason: filter.reason})};
-
+    {
+      return {error: new FilterParsingError("invalid-filter",

[Sebastian Noack, 2017/02/09 01:04:51]

It seems we could turn four lines into three and avoid ugly wrapping, if you
destructure the filter above.

[kzar, 2017/02/20 10:27:32]

I just tried it but unfortunately the invalid-css-selector line is still one
character too long for ESLint. We could give the selector variable an
abbreviated name but I'm not sure if that's better than what we have now.

+                                            {reason: filter.reason})};
+    }
     if (filter instanceof ElemHideBase && !isValidCSSSelector(filter.selector))
-      return {error: new FilterParsingError("invalid-css-selector", {selector: filter.selector})};
+    {
+      return {error: new FilterParsingError("invalid-css-selector",
+                                            {selector: filter.selector})};
+    }
   }
 
-  return {filter: filter};
+  return {filter};
 };
 
 /**
  * @typedef ParsedFilters
  * @property {Filter[]} filters  The parsed result without invalid filters.
- * @property {FilterParsingError[]} errors  See {@link module:filterValidation~FilterParsingError FilterParsingError}
+ * @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 = 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};
+  return {filters, errors};
 };