Issue 4864 - Start using ESLint for adblockpluschrome

lib/filterComposer.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 22 matching lines @@
  * Checks whether the given page is ready to use the filter composer
  *
  * @param {Page} page
  * @return {boolean}
  */
 exports.isPageReady = page =>
 {
   return readyPages.has(page);
 };
 
-function isValidString(s) {
+function isValidString(s)
+{
   return s && s.indexOf("\0") == -1;
 }
 
 function escapeChar(chr)
 {
   let code = chr.charCodeAt(0);
 
   // Control characters and leading digits must be escaped based on
   // their char code in CSS. Moreover, curly brackets aren't allowed
   // in elemhide filters, and therefore must be escaped based on their
   // char code as well.
-  if (code <= 0x1F || code == 0x7F || /[\d\{\}]/.test(chr))
+  if (code <= 0x1F || code == 0x7F || /[\d{}]/.test(chr))
     return "\\" + code.toString(16) + " ";
 
   return "\\" + chr;
 }
 
 let escapeCSS =
 /**
- * Escapes a token (e.g. tag, id, class or attribute) to be used in CSS selectors.
+ * Escapes a token (e.g. tag, id, class or attribute) to be used in
+ * CSS selectors.
  *
  * @param {string} s
  * @return {string}
  * @static
  */
 exports.escapeCSS = s =>
 {
-  return s.replace(/^[\d\-]|[^\w\-\u0080-\uFFFF]/g, escapeChar);
+  return s.replace(/^[\d-]|[^\w\-\u0080-\uFFFF]/g, escapeChar);
 };
 
 let quoteCSS =
 /**
  * Quotes a string to be used as attribute value in CSS selectors.
  *
  * @param {string} value
  * @return {string}
  * @static
  */
 exports.quoteCSS = value =>
 {
-  return '"' + value.replace(/["\\\{\}\x00-\x1F\x7F]/g, escapeChar) + '"';
+  return '"' + value.replace(/["\\{}\x00-\x1F\x7F]/g, escapeChar) + '"';
 };
 
 function composeFilters(details)
 {
+  let {page, frame} = details;
   let filters = [];
   let selectors = [];
 
-  let page = details.page;
-  let frame = details.frame;
-
   if (!checkWhitelisted(page, frame))
   {
     let typeMask = RegExpFilter.typeMap[details.type];
     let docDomain = extractHostFromFrame(frame);
-    let specificOnly = checkWhitelisted(page, frame, RegExpFilter.typeMap.GENERICBLOCK);
+    let specificOnly = checkWhitelisted(page, frame,
+                                        RegExpFilter.typeMap.GENERICBLOCK);
 
     // Add a blocking filter for each URL of the element that can be blocked
     for (let url of details.urls)
     {
       let urlObj = new URL(url, details.baseURL);
       url = stringifyURL(urlObj);
 
       let filter = defaultMatcher.whitelist.matchesAny(
         url, typeMask, docDomain,
         isThirdParty(urlObj, docDomain),
         getKey(page, frame), specificOnly
       );
 
       if (!filter)
       {
-        let filterText = url.replace(/^[\w\-]+:\/+(?:www\.)?/, "||");
+        let filterText = url.replace(/^[\w-]+:\/+(?:www\.)?/, "||");
 
         if (specificOnly)
           filterText += "$domain=" + docDomain;
 
         if (filters.indexOf(filterText) == -1)
           filters.push(filterText);
       }
     }
 
     // If we couldn't generate any blocking filters, fallback to element hiding
-    let selectors = [];
-    if (filters.length == 0 && !checkWhitelisted(page, frame, RegExpFilter.typeMap.ELEMHIDE))
+    if (filters.length == 0 && !checkWhitelisted(page, frame,
+                                                 RegExpFilter.typeMap.ELEMHIDE))
     {
-      // Generate CSS selectors based on the element's "id" and "class" attribute
+      // Generate CSS selectors based on the element's "id" and
+      // "class" attribute.
       if (isValidString(details.id))
         selectors.push("#" + escapeCSS(details.id));
 
       let classes = details.classes.filter(isValidString);
       if (classes.length > 0)
         selectors.push(classes.map(c => "." + escapeCSS(c)).join(""));
 
       // If there is a "src" attribute, specifiying a URL that we can't block,
       // generate a CSS selector matching the "src" attribute
       if (isValidString(details.src))
-        selectors.push(escapeCSS(details.tagName) + "[src=" + quoteCSS(details.src) + "]");
+      {
+        selectors.push(
+          escapeCSS(details.tagName) + "[src=" + quoteCSS(details.src) + "]"
+        );
+      }
 
-      // As last resort, if there is a "style" attribute, and we couldn't generate
-      // any filters so far, generate a CSS selector matching the "style" attribute
-      if (isValidString(details.style) && selectors.length == 0 && filters.length == 0)
-        selectors.push(escapeCSS(details.tagName) + "[style=" + quoteCSS(details.style) + "]");
+      // As last resort, if there is a "style" attribute, and we
+      // couldn't generate any filters so far, generate a CSS selector
+      // matching the "style" attribute
+      if (isValidString(details.style) && selectors.length == 0 &&
+          filters.length == 0)
+      {
+        selectors.push(
+          escapeCSS(details.tagName) + "[style=" + quoteCSS(details.style) + "]"
+        );
+      }
 
       // Add an element hiding filter for each generated CSS selector
       for (let selector of selectors)
         filters.push(docDomain.replace(/^www\./, "") + "##" + selector);
     }
   }
 
-  return {filters: filters, selectors: selectors};
+  return {filters, selectors};
 }
 
 let contextMenuItem = {
   title: ext.i18n.getMessage("block_element"),
   contexts: ["image", "video", "audio"],
   onclick(page)
   {
     page.sendMessage({type: "composer.content.contextMenuClicked"});
   }
 };
@@ skipping 54 matching lines @@
       ext.pages.onRemoved.addListener(onRemoved);
       resolve(popupPageId);
     });
   });
 });
 
 port.on("composer.getFilters", (message, sender) =>
 {
   return composeFilters({
     tagName: message.tagName,
-    id:      message.id,

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

Could we perhaps break this down to two lines, if we use desctructuring +
shorthand syntax? Otherwise, I think it is fine as it is.

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

I know what you mean but I wonder if assigning a bunch of variables just to save
a few lines is worth it.

-    src:     message.src,
-    style:   message.style,
+    id: message.id,
+    src: message.src,
+    style: message.style,
     classes: message.classes,
-    urls:    message.urls,
-    type:    message.mediatype,
+    urls: message.urls,
+    type: message.mediatype,
     baseURL: message.baseURL,
-    page:    sender.page,
-    frame:   sender.frame
+    page: sender.page,
+    frame: sender.frame
   });
 });
 
 ext.pages.onLoading.addListener(page =>
 {
   page.sendMessage({type: "composer.content.finished"});
 });