Fix bug with process.nextTick referencing the wrong function. (#10)

* Fix bug with process.nextTick referencing the wrong function.

`lolex` and by extension `sinon` fake timers, change the value of
`process.nextTick` in order to properly be added to the fake event loop stack.
The previous way this module was written kept a reference to the original
function and didn't look up the current value of `process.nextTick`. This
commit makes each invocation of nextTick look up the current value of
`process.nextTick`.

* Revert polyfill and add a wrapper for the real nextTick.

* Use wrapper that defaults to process on newish nodes.

Author: kolodny

index.js

@@ -3,9 +3,9 @@
 if (!process.version ||
     process.version.indexOf('v0.') === 0 ||
     process.version.indexOf('v1.') === 0 && process.version.indexOf('v1.8.') !== 0) {
-  module.exports = nextTick;
+  module.exports = { nextTick: nextTick };
 } else {
-  module.exports = process.nextTick;
+  module.exports = process
 }
 
 function nextTick(fn, arg1, arg2, arg3) {
@@ -41,3 +41,4 @@ function nextTick(fn, arg1, arg2, arg3) {
     });
   }
 }
+

readme.md

@@ -10,9 +10,9 @@ npm install --save process-nextick-args
 Always be able to pass arguments to process.nextTick, no matter the platform
 
 ```js
-var nextTick = require('process-nextick-args');
+var pna = require('process-nextick-args');
 
-nextTick(function (a, b, c) {
+pna.nextTick(function (a, b, c) {
   console.log(a, b, c);
 }, 'step', 3,  'profit');
 ```

test.js

@@ -1,15 +1,15 @@
 var test = require("tap").test;
-var nextTick = require('./');
+var pna = require('./');
 
 test('should work', function (t) {
   t.plan(5);
-  nextTick(function (a) {
+  pna.nextTick(function (a) {
     t.ok(a);
-    nextTick(function (thing) {
+    pna.nextTick(function (thing) {
       t.equals(thing, 7);
     }, 7);
   }, true);
-  nextTick(function (a, b, c) {
+  pna.nextTick(function (a, b, c) {
     t.equals(a, 'step');
     t.equals(b, 3);
     t.equals(c, 'profit');
@@ -18,7 +18,19 @@ test('should work', function (t) {
 
 test('correct number of arguments', function (t) {
   t.plan(1);
-  nextTick(function () {
+  pna.nextTick(function () {
     t.equals(2, arguments.length, 'correct number');
   }, 1, 2);
 });
+
+test('uses the current value of process.nextTick', function (t) {
+  t.plan(1);
+  var oldNextTick = process.nextTick;
+  var called = false;
+  process.nextTick = function() {
+    called = true
+  };
+  pna.nextTick(function () {});
+  process.nextTick = oldNextTick;
+  t.ok(called);
+});