fixing behavior of nbind binding

Author: davidpadbury

q.js

@@ -1410,14 +1410,13 @@ function nfbind(callback/*, ...args */) {
 }
 
 Q.nbind = nbind;
-function nbind(callback/*, ... args*/) {
-    var baseArgs = array_slice(arguments, 1);
+function nbind(callback, thisArg /*, ... args*/) {
+    var baseArgs = array_slice(arguments, 2);
     return function () {
         var nodeArgs = baseArgs.concat(array_slice(arguments));
         var deferred = defer();
         nodeArgs.push(deferred.makeNodeResolver());
 
-        var thisArg = this;
         function bound() {
             return callback.apply(thisArg, arguments);
         }

spec/q-spec.js

@@ -1919,11 +1919,12 @@ describe("node support", function () {
     describe("nbind", function () {
 
         it("binds this, and mixes partial application with complete application", function () {
-            return Q.nbind(function (a, b, c, d, callback) {
-                callback(null, this + a + b + c + d);
-            }, 1, 2).call(3, 4, 5)
-            .then(function (fifteen) {
-                expect(fifteen).toBe(15);
+            return Q.nbind(function (a, b, c, callback) {
+                console.log(this, arguments);
+                callback(null, this + a + b + c);
+            }, 1, 2).call(3 /* effectively ignored as fn bound to 1 */, 4, 5)
+            .then(function (twelve) {
+                expect(twelve).toBe(12);
             });
         });