Issue 4864 - Start using ESLint for adblockpluschrome

chrome/ext/background.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 39 matching lines @@
     sendMessage(message, responseCallback)
     {
       chrome.tabs.sendMessage(this.id, message, responseCallback);
     }
   };
 
   ext.getPage = id => new Page({id: parseInt(id, 10)});
 
   function afterTabLoaded(callback)
   {
-     return openedTab =>
-     {
-       let onUpdated = (tabId, changeInfo, tab) =>
-       {
-         if (tabId == openedTab.id && changeInfo.status == "complete")
-         {
-           chrome.tabs.onUpdated.removeListener(onUpdated);
-           callback(new Page(openedTab));
-         }
-       };
-       chrome.tabs.onUpdated.addListener(onUpdated);
-     };
+    return openedTab =>
+    {
+      let onUpdated = (tabId, changeInfo, tab) =>
+      {
+        if (tabId == openedTab.id && changeInfo.status == "complete")
+        {
+          chrome.tabs.onUpdated.removeListener(onUpdated);
+          callback(new Page(openedTab));
+        }
+      };
+      chrome.tabs.onUpdated.addListener(onUpdated);
+    };
   }
 
   ext.pages = {
     open(url, callback)
     {
-      chrome.tabs.create({url: url}, callback && afterTabLoaded(callback));
+      chrome.tabs.create({url}, callback && afterTabLoaded(callback));
     },
     query(info, callback)
     {
       let rawInfo = {};
       for (let property in info)
       {
         switch (property)
         {
           case "active":
           case "lastFocusedWindow":
@@ skipping 36 matching lines @@
     let frame = createFrame(details.tabId, details.frameId);
     frame.parent = framesOfTabs[details.tabId][details.parentFrameId] || null;
   });
 
   let eagerlyUpdatedPages = new ext.PageMap();
 
   ext._updatePageFrameStructure = (frameId, tabId, url, eager) =>
   {
     if (frameId == 0)
     {
-      let page = new Page({id: tabId, url: url});
+      let page = new Page({id: tabId, url});
 
       if (eagerlyUpdatedPages.get(page) != url)
       {
         ext._removeFromAllPageMaps(tabId);
 
         // When a sitekey header is received we must immediately update the page
         // structure in order to record and use the key. We want to avoid
         // trashing the page structure if the onCommitted event is then fired
         // for the page.
         if (eager)
           eagerlyUpdatedPages.set(page, url);
 
         chrome.tabs.get(tabId, () =>
         {
           // If the tab is prerendered, chrome.tabs.get() sets
-          // chrome.runtime.lastError and we have to dispatch the onLoading event,
-          // since the onUpdated event isn't dispatched for prerendered tabs.
-          // However, we have to keep relying on the unUpdated event for tabs that
-          // are already visible. Otherwise browser action changes get overridden
-          // when Chrome automatically resets them on navigation.
+          // chrome.runtime.lastError and we have to dispatch the
+          // onLoading event, since the onUpdated event isn't
+          // dispatched for prerendered tabs.  However, we have to
+          // keep relying on the unUpdated event for tabs that are
+          // already visible. Otherwise browser action changes get
+          // overridden when Chrome automatically resets them on
+          // navigation.
           if (chrome.runtime.lastError)
             ext.pages.onLoading._dispatch(page);
         });
       }
     }
 
     // Update frame URL in frame structure
     let frame = createFrame(tabId, frameId);
     frame.url = new URL(url);
   };
@@ skipping 62 matching lines @@
         chrome.browserAction.setBadgeBackgroundColor({
           tabId: this._tabId,
           color: this._changes.badgeColor
         });
       }
 
       this._changes = null;
     },
     _queueChanges()
     {
-      chrome.tabs.get(this._tabId, function()
+      chrome.tabs.get(this._tabId, () =>
       {
         // If the tab is prerendered, chrome.tabs.get() sets
         // chrome.runtime.lastError and we have to delay our changes
         // until the currently visible tab is replaced with the
         // prerendered tab. Otherwise chrome.browserAction.set* fails.
         if (chrome.runtime.lastError)
         {
           let onReplaced = (addedTabId, removedTabId) =>
           {
             if (addedTabId == this._tabId)
             {
               chrome.tabs.onReplaced.removeListener(onReplaced);
               this._applyChanges();
             }
           };
           chrome.tabs.onReplaced.addListener(onReplaced);
         }
         else
         {
           this._applyChanges();
         }
-      }.bind(this));
+      });
     },
     _addChange(name, value)
     {
       if (!this._changes)
       {
         this._changes = {};
         this._queueChanges();
       }
 
       this._changes[name] = value;
@@ skipping 101 matching lines @@
 
   /* Web requests */
 
   let framesOfTabs = Object.create(null);
 
   ext.getFrame = (tabId, frameId) =>
   {
     return (framesOfTabs[tabId] || {})[frameId];
   };
 
-  let handlerBehaviorChangedQuota = chrome.webRequest.MAX_HANDLER_BEHAVIOR_CHANGED_CALLS_PER_10_MINUTES;
+  let handlerBehaviorChangedQuota = (
+    chrome.webRequest.MAX_HANDLER_BEHAVIOR_CHANGED_CALLS_PER_10_MINUTES
+  );

[Sebastian Noack, 2017/02/09 01:04:49]

The parenthesis here seem unnecessary.

[kzar, 2017/02/20 10:27:29]

Done.

 
   function propagateHandlerBehaviorChange()
   {
     // Make sure to not call handlerBehaviorChanged() more often than allowed
     // by chrome.webRequest.MAX_HANDLER_BEHAVIOR_CHANGED_CALLS_PER_10_MINUTES.
     // Otherwise Chrome notifies the user that this extension is causing issues.
     if (handlerBehaviorChangedQuota > 0)
     {
-      chrome.webNavigation.onBeforeNavigate.removeListener(propagateHandlerBehaviorChange);
+      chrome.webNavigation.onBeforeNavigate.removeListener(
+        propagateHandlerBehaviorChange

[Sebastian Noack, 2017/02/09 01:04:49]

I wonder whether we can perhaps shorten the variable name, rather than awkwardly
wrapping those lines. The variable name can be up to 19 characters in order to
avoid exceeding 80 characters total.

[kzar, 2017/02/20 10:27:28]

I don't mind the wrapping too much here and I can't think of a better name. But
I don't mind changing the name if you can think of something shorter either.

+      );
       chrome.webRequest.handlerBehaviorChanged();
 
       handlerBehaviorChangedQuota--;
       setTimeout(() => { handlerBehaviorChangedQuota++; }, 600000);
     }
   }
 
   ext.webRequest = {
     onBeforeRequest: new ext._EventTarget(),
     handlerBehaviorChanged()
     {
       // Defer handlerBehaviorChanged() until navigation occurs.
       // There wouldn't be any visible effect when calling it earlier,
       // but it's an expensive operation and that way we avoid to call
       // it multiple times, if multiple filters are added/removed.
-      let onBeforeNavigate = chrome.webNavigation.onBeforeNavigate;
+      let {onBeforeNavigate} = chrome.webNavigation;
       if (!onBeforeNavigate.hasListener(propagateHandlerBehaviorChange))
         onBeforeNavigate.addListener(propagateHandlerBehaviorChange);
     }
   };
 
   chrome.tabs.query({}, tabs =>
   {
     tabs.forEach(tab =>
     {
       chrome.webNavigation.getAllFrames({tabId: tab.id}, details =>
       {
         if (details && details.length > 0)
         {
           let frames = framesOfTabs[tab.id] = Object.create(null);
 
           for (let i = 0; i < details.length; i++)
-            frames[details[i].frameId] = {url: new URL(details[i].url), parent: null};
+          {
+            frames[details[i].frameId] = {
+              url: new URL(details[i].url),
+              parent: null
+            };
+          }
 
           for (let i = 0; i < details.length; i++)
           {
-            let parentFrameId = details[i].parentFrameId;
+            let {parentFrameId} = details[i];
 
             if (parentFrameId != -1)
               frames[details[i].frameId].parent = frames[parentFrameId];
           }
         }
       });
     });
   });
 
   chrome.webRequest.onBeforeRequest.addListener(details =>
   {
     // The high-level code isn't interested in requests that aren't
     // related to a tab or requests loading a top-level document,
     // those should never be blocked.
     if (details.tabId == -1 || details.type == "main_frame")
       return;
 
     // We are looking for the frame that contains the element which
     // has triggered this request. For most requests (e.g. images) we
     // can just use the request's frame ID, but for subdocument requests
     // (e.g. iframes) we must instead use the request's parent frame ID.
-    let frameId;
-    let requestType;
-    if (details.type == "sub_frame")
+    let {frameId, type} = details;
+    if (type == "sub_frame")
     {
       frameId = details.parentFrameId;
-      requestType = "SUBDOCUMENT";
-    }
-    else
-    {
-      frameId = details.frameId;
-      requestType = details.type.toUpperCase();
+      type = "SUBDOCUMENT";
     }
 
     let frame = ext.getFrame(details.tabId, frameId);
     if (frame)
     {
       let results = ext.webRequest.onBeforeRequest._dispatch(
         new URL(details.url),
-        requestType,
+        type.toUpperCase(),
         new Page({id: details.tabId}),
         frame
       );
 
       if (results.indexOf(false) != -1)
         return {cancel: true};
     }
   }, {urls: ["http://*/*", "https://*/*"]}, ["blocking"]);
 
 
@@ skipping 19 matching lines @@
 
           let frame = frames[rawSender.frameId];
           if (frame)
             return frame.parent;
 
           return frames[0];
         }
       };
     }
 
-    return ext.onMessage._dispatch(message, sender, sendResponse).indexOf(true) != -1;
+    let results = ext.onMessage._dispatch(message, sender, sendResponse);
+    return results.indexOf(true) != -1;

[Sebastian Noack, 2017/02/09 01:04:48]

This would be another way to wrap the code here, without a temporary variable:

  return ext.onMessage._dispatch(message,
                                 sender,
                                 sendResponse).indexOf(true) != -1;

No strong opinion though. What do you think?

[kzar, 2017/02/20 10:27:29]

I've wrapped it in a similar way which I preferred, that OK?

   });
 
 
   /* Storage */
 
   ext.storage = {
     get(keys, callback)
     {
       chrome.storage.local.get(keys, callback);
     },
@@ skipping 83 matching lines @@
   ext.windows = {
     create(createData, callback)
     {
       chrome.windows.create(createData, createdWindow =>
       {
         afterTabLoaded(callback)(createdWindow.tabs[0]);
       });
     }
   };
 }