Issue 1434 - Remove some non-standard JS usage from buildtools.

lib/keySelector.js

Index: lib/keySelector.js
===================================================================
--- a/lib/keySelector.js
+++ b/lib/keySelector.js
@@ -88,49 +88,63 @@ KeySelector.prototype =
 
       let keyCode = key.getAttribute("keycode");
       if (keyCode && "DOM_" + keyCode.toUpperCase() in Ci.nsIDOMKeyEvent)
         keyData.code = Ci.nsIDOMKeyEvent["DOM_" + keyCode.toUpperCase()];
 
       if (!keyData.char && !keyData.code)
         continue;
 
-      let keyModifiers = key.getAttribute("modifiers");
-      if (keyModifiers)
-        for each (let modifier in keyModifiers.toUpperCase().match(/\w+/g))
+      let modifiers = key.getAttribute("modifiers");
+      modifiers = modifiers ? modifiers.toUpperCase().match(/\w+/g) : null;

[Wladimir Palant, 2014/11/17 20:05:17]

If you are doing it this way, why not use [] instead of null? Then you don't
need the if block below any more.

+      if (modifiers)
+      {
+        for (let modifier of modifiers)
+        {
           if (modifier in validModifiers)
             keyData[validModifiers[modifier]] = true;
+        }
+      }
 
       let canonical = [keyData.shift, keyData.meta, keyData.alt, keyData.control, keyData.char || keyData.code].join(" ");
       this._existingShortcuts[canonical] = true;
     }
   },
 
   /**
    * Selects a keyboard shortcut variant that isn't already taken,
    * parses it into an object.
    */
   selectKey: function(/**String*/ variants) /**Object*/
   {
-    for each (let variant in variants.split(/\s*,\s*/))
+    variants = variants.split(/\s*,\s*/);
+    if (!variants)

[Wladimir Palant, 2014/11/17 20:05:17]

This condition can never be true - String.split() always returns an array with
at least one entry.

+      return null;
+
+    for (let variant of variants)
     {
       if (!variant)
         continue;
 
       let keyData =
       {
         shift: false,
         meta: false,
         alt: false,
         control: false,
         char: null,
         code: null,
         codeName: null
       };
-      for each (let part in variant.toUpperCase().split(/\s+/))
+
+      variant = variant.toUpperCase().split(/\s+/);
+      if (!variant)

[Wladimir Palant, 2014/11/17 20:05:17]

Same here, this if block is pointless.

+        continue;
+
+      for (let part of variant)
       {
         if (part in validModifiers)
           keyData[validModifiers[part]] = true;
         else if (part.length == 1)
           keyData.char = part;
         else if ("DOM_VK_" + part in Ci.nsIDOMKeyEvent)
         {
           keyData.code = Ci.nsIDOMKeyEvent["DOM_VK_" + part];