process: throw on non-function to nextTick()

This commit causes process.nextTick() to throw when its callback
argument is not a function.

PR-URL: #3860
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>

src/node.js

@@ -486,6 +486,8 @@
     }
 
     function nextTick(callback) {
+      if (typeof callback !== 'function')
+        throw new TypeError('callback is not a function');
       // on the way out, don't bother. it won't get fired anyway.
       if (process._exiting)
         return;

test/parallel/test-next-tick-errors.js

@@ -20,6 +20,22 @@ process.nextTick(function() {
   order.push('C');
 });
 
+function testNextTickWith(val) {
+  assert.throws(
+    function() {
+      process.nextTick(val);
+    },
+    TypeError
+  );
+}
+
+testNextTickWith(false);
+testNextTickWith(true);
+testNextTickWith(1);
+testNextTickWith('str');
+testNextTickWith({});
+testNextTickWith([]);
+
 process.on('uncaughtException', function() {
   if (!exceptionHandled) {
     exceptionHandled = true;