Issue 4579 - Promisify APIs

polyfill.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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 25 matching lines @@
     "tabs.query",
     "tabs.reload",
     "tabs.sendMessage",
     "tabs.update",
     "webNavigation.getAllFrames",
     "webRequest.handlerBehaviorChanged",
     "windows.create",
     "windows.update"
   ];
 
-  let wrapAPI = api =>
+  function wrapAPI(api)
   {
     let object = browser;
     let path = api.split(".");
     let name = path.pop();
 
     for (let node of path)
     {
       object = object[node];
 
       if (!object)
@@ skipping 19 matching lines @@
         func.call(object, ...args, result =>
         {
           let error = browser.runtime.lastError;
           if (error)
             reject(error);
           else
             resolve(result);
         });
       });
     };
-  };
+  }
 
-  let shouldWrapAPIs = () =>
+  function shouldWrapAPIs()
   {
     try
     {
       return !(browser.storage.local.get([]) instanceof Promise);
     }
     catch (error)
     {
     }
 
     return true;

[Wladimir Palant, 2017/10/18 08:59:11]

Nit: I would put that return inside the catch block which makes the logic
clearer IMHO.

[Manish Jethani, 2017/10/18 11:00:26]

Acknowledged.

-  };
+  }
 
   if (shouldWrapAPIs())
   {
     // Unlike Firefox and Microsoft Edge, Chrome doesn't have a "browser" object,
     // but provides the extension API through the "chrome" namespace
     // (non-standard).
     if (typeof browser == "undefined")
       window.browser = chrome;
 
     for (let api of asyncAPIs)
       wrapAPI(api);
   }
 
   // Workaround since HTMLCollection, NodeList, StyleSheetList, and CSSRuleList
   // didn't have iterator support before Chrome 51.
   // https://bugs.chromium.org/p/chromium/issues/detail?id=401699
   for (let object of [HTMLCollection, NodeList, StyleSheetList, CSSRuleList])
   {
     if (!(Symbol.iterator in object.prototype))
       object.prototype[Symbol.iterator] = Array.prototype[Symbol.iterator];
   }
 }