Allow NaN (#94)

* Test encoding and decoding NaN

* Encode NaN

lib/encoder.js

@@ -2,13 +2,11 @@
 
 var Buffer = require('safe-buffer').Buffer
 var bl = require('bl')
-var isNaN = require('./helpers.js').isNaN
 var isFloat = require('./helpers.js').isFloat
 
 module.exports = function buildEncode (encodingTypes, options) {
   function encode (obj) {
     if (obj === undefined) throw new Error('undefined is not encodable in msgpack!')
-    if (isNaN(obj)) throw new Error('NaN is not encodable in msgpack!')
 
     if (obj === null) return Buffer.from([ 0xc0 ])
     if (obj === true) return Buffer.from([ 0xc3 ])
@@ -133,7 +131,7 @@ const fround = Math.fround
 function encodeFloat (obj, forceFloat64) {
   var buf
 
-  if (forceFloat64 || !fround || fround(obj) !== obj) {
+  if (forceFloat64 || !fround || !Object.is(fround(obj), obj)) {
     buf = Buffer.allocUnsafe(9)
     buf[0] = 0xcb
     buf.writeDoubleBE(obj, 1)

lib/helpers.js

@@ -18,9 +18,3 @@ util.inherits(IncompleteBufferError, Error)
 exports.isFloat = function isFloat (n) {
   return n % 1 !== 0
 }
-
-exports.isNaN = function isNaN (n) {
-  /* eslint-disable no-self-compare */
-  return n !== n && typeof n === 'number'
-  /* eslint-enable no-self-compare */
-}

test/15-elements-maps.js

@@ -71,13 +71,21 @@ test('do not encode undefined in a map', function (t) {
   t.end()
 })
 
-test('throw error on NaN in a map', function (t) {
+test('encode 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')
+  const buf = instance.encode(toEncode)
+
+  t.assert(Object.is(instance.decode(buf).a, NaN))
+
+  const expected = {...toEncode}
+  delete toEncode.a
+  const actual = instance.decode(buf)
+  delete buf.a
+
+  t.deepEqual(actual, expected)
+
   t.end()
 })
 

test/NaN.js

@@ -3,12 +3,50 @@
 var test = require('tape').test
 var msgpack = require('../')
 
-test('encode NaN', function (t) {
-  var encoder = msgpack()
+test('encode NaN as 32-bit float', function (t) {
+  const encoder = msgpack()
 
-  t.throws(function () {
-    encoder.encode(NaN)
-  }, Error, 'must throw Error')
+  const buf = encoder.encode(NaN)
+  t.equal(buf[0], 0xca)
+  t.equal(buf.byteLength, 5)
+
+  t.end()
+})
+
+test('encode NaN as 64-bit float with forceFloat64', function (t) {
+  const encoder = msgpack({forceFloat64: true})
+
+  const buf = encoder.encode(NaN)
+
+  t.equal(buf[0], 0xcb)
+  t.equal(buf.byteLength, 9)
+
+  t.end()
+})
+
+test('round-trip 32-bit NaN', function (t) {
+  const encoder = msgpack()
+
+  t.assert(Object.is(encoder.decode(encoder.encode(NaN)), NaN))
+
+  t.end()
+})
+
+test('round-trip 64-bit NaN with forceFloat64', function (t) {
+  const encoder = msgpack({forceFloat64: true})
+
+  t.assert(Object.is(encoder.decode(encoder.encode(NaN)), NaN))
+
+  t.end()
+})
+
+test('decode 64-bit NaN', function (t) {
+  const encoder = msgpack()
+  const buf = Buffer.alloc(9)
+  buf.writeUInt8(0xcb, 0)
+  buf.writeDoubleBE(NaN, 1)
+
+  t.assert(Object.is(encoder.decode(buf), NaN))
 
   t.end()
 })