events: do not accept NaN in setMaxListeners

lib/events.js

@@ -45,7 +45,7 @@ exports.EventEmitter = EventEmitter;
 // that to be increased. Set to zero for unlimited.
 var defaultMaxListeners = 10;
 EventEmitter.prototype.setMaxListeners = function(n) {
-  if (typeof n !== 'number' || n < 0)
+  if (typeof n !== 'number' || n < 0 || isNaN(n))
     throw TypeError('n must be a positive number');
   this._maxListeners = n;
 };

test/simple/test-event-emitter-max-listeners.js

@@ -38,4 +38,16 @@ e.on('maxListeners', function() {
 // Should not corrupt the 'maxListeners' queue.
 e.setMaxListeners(42);
 
+assert.throws(function() {
+  e.setMaxListeners(NaN);
+});
+
+assert.throws(function() {
+  e.setMaxListeners(-1);
+});
+
+assert.throws(function() {
+  e.setMaxListeners("and even this");
+});
+
 e.emit('maxListeners');