small performance improvements

lib/6to5/transformation/modules/common-interop.js

@@ -22,8 +22,7 @@ CommonJSInteropFormatter.prototype.importSpecifier = function (specifier, node,
         })])
       )
     ]));
-    return;
+  } else {
+    CommonJSFormatter.prototype.importSpecifier.apply(this, arguments);
   }
-
-  CommonJSFormatter.prototype.importSpecifier.apply(this, arguments);
 };

lib/6to5/transformation/transformers/_declarations.js

@@ -4,9 +4,10 @@ var _ = require("lodash");
 module.exports = function (ast, file) {
   var body = ast.program.body;
 
-  _.each(file.declarations, function (declar) {
+  for (var i in file.declarations) {
+    var declar = file.declarations[i];
     body.unshift(t.variableDeclaration("var", [
       t.variableDeclarator(declar.uid, declar.node)
     ]));
-  });
+  }
 };

lib/6to5/transformation/transformers/template-literals.js

@@ -22,9 +22,7 @@ exports.TaggedTemplateExpression = function (node, parent, file) {
     t.arrayExpression(raw)
   ]));
 
-  _.each(quasi.expressions, function (expr) {
-    args.push(expr);
-  });
+  args = args.concat(quasi.expressions);
 
   return t.callExpression(node.tag, args);
 };