Issue 4864 - Start using ESLint for adblockpluschrome

lib/filterComposer.js

Index: lib/filterComposer.js
diff --git a/lib/filterComposer.js b/lib/filterComposer.js
index 454204a2989159ed3d3e8c58e726a7795594bc5c..fb018c65b86467f92e726317fff044f9139cb6e3 100644
--- a/lib/filterComposer.js
+++ b/lib/filterComposer.js
@@ -40,7 +40,8 @@ exports.isPageReady = page =>
   return readyPages.has(page);
 };
 
-function isValidString(s) {
+function isValidString(s)
+{
   return s && s.indexOf("\0") == -1;
 }
 
@@ -52,7 +53,7 @@ function escapeChar(chr)
   // 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;
@@ -60,7 +61,8 @@ function escapeChar(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}
@@ -68,7 +70,7 @@ let escapeCSS =
  */
 exports.escapeCSS = s =>
 {
-  return s.replace(/^[\d\-]|[^\w\-\u0080-\uFFFF]/g, escapeChar);
+  return s.replace(/^[\d-]|[^\w\-\u0080-\uFFFF]/g, escapeChar);
 };
 
 let quoteCSS =
@@ -81,22 +83,21 @@ let quoteCSS =
  */
 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)
@@ -112,7 +113,7 @@ function composeFilters(details)
 
       if (!filter)
       {
-        let filterText = url.replace(/^[\w\-]+:\/+(?:www\.)?/, "||");
+        let filterText = url.replace(/^[\w-]+:\/+(?:www\.)?/, "||");
 
         if (specificOnly)
           filterText += "$domain=" + docDomain;
@@ -123,10 +124,11 @@ function composeFilters(details)
     }
 
     // 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));
 
@@ -137,12 +139,22 @@ function composeFilters(details)
       // 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)
@@ -150,7 +162,7 @@ function composeFilters(details)
     }
   }
 
-  return {filters: filters, selectors: selectors};
+  return {filters, selectors};
 }
 
 let contextMenuItem = {
@@ -225,15 +237,15 @@ 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
   });
 });