Handle NaN (#75)

* Handle NaN

* Throw error when map contains NaN

lib/encoder.js

@@ -10,6 +10,8 @@ module.exports = function buildEncode (encodingTypes, forceFloat64, compatibilit
 
     if (obj === undefined) {
       throw new Error('undefined is not encodable in msgpack!')
+    } else if (isNaN(obj)) {
+      throw new Error('NaN is not encodable in msgpack!')
     } else if (obj === null) {
       buf = Buffer.allocUnsafe(1)
       buf[0] = 0xc0
@@ -303,6 +305,12 @@ function isFloat (n) {
   return n % 1 !== 0
 }
 
+function isNaN (n) {
+  /* eslint-disable no-self-compare */
+  return n !== n && typeof n === 'number'
+  /* eslint-enable no-self-compare */
+}
+
 function encodeFloat (obj, forceFloat64) {
   var useDoublePrecision = true
 

test/15-elements-maps.js

@@ -71,6 +71,16 @@ test('do not encode undefined in a map', function (t) {
   t.end()
 })
 
+test('throw error on NaN in a map', function (t) {
+  var instance = msgpack()
+  var toEncode = { a: NaN, hello: 'world' }
+
+  t.throws(function () {
+    instance.encode(toEncode)
+  }, Error, 'must throw Error')
+  t.end()
+})
+
 test('encode/decode map with buf, ints and strings', function (t) {
   var map = {
     topic: 'hello',

test/NaN.js

@@ -0,0 +1,14 @@
+'use strict'
+
+var test = require('tape').test
+var msgpack = require('../')
+
+test('encode NaN', function (t) {
+  var encoder = msgpack()
+
+  t.throws(function () {
+    encoder.encode(NaN)
+  }, Error, 'must throw Error')
+
+  t.end()
+})