Enable non-object JSON bodies

Updated JSON requests so they can contain bodies that are not objects. For avoid unexpected surprises, JSON `null` values are not sent.

.gitignore

@@ -1 +1,2 @@
 node_modules
+.idea

request.js

@@ -1481,7 +1481,7 @@ Request.prototype.json = function (val) {
 
   self._json = true
   if (typeof val === 'boolean') {
-    if (typeof self.body === 'object') {
+    if (self.body !== undefined && self.body !== null) {
       self.body = safeStringify(self.body)
       if (!self.hasHeader('content-type')) {
         self.setHeader('content-type', 'application/json')

tests/test-json-request.js

@@ -0,0 +1,47 @@
+'use strict'
+
+var server = require('./server')
+  , stream = require('stream')
+  , request = require('../index')
+  , tape = require('tape')
+
+var s = server.createServer()
+
+tape('setup', function(t) {
+  s.listen(s.port, function() {
+    t.end()
+  })
+})
+
+tape('test testPutBoolean', function(t) {
+  s.on('/testPutBoolean', server.createPostValidator('true', 'application/json'))
+  var opts = {
+    method: 'PUT',
+    uri: s.url + '/testPutBoolean',
+    json: true,
+    body: true
+  }
+  request(opts, function (err, resp, body) {
+    t.equal(err, null)
+    t.end()
+  })
+})
+
+tape('test testPutNull', function(t) {
+  s.on('/testPutNull', server.createPostValidator(''))
+  var opts = {
+    method: 'PUT',
+    uri: s.url + '/testPutNull',
+    json: true,
+    body: null
+  }
+  request(opts, function (err, resp, body) {
+    t.equal(err, null)
+    t.end()
+  })
+})
+
+tape('cleanup', function(t) {
+  s.close()
+  t.end()
+})