Support JSON stringify replacer argument.

README.md

@@ -749,6 +749,7 @@ The first argument can be either a `url` or an `options` object. The only requir
 - `postambleCRLF` - append a newline/CRLF at the end of the boundary of your `multipart/form-data` request.
 - `json` - sets `body` to JSON representation of value and adds `Content-type: application/json` header.  Additionally, parses the response body as JSON.
 - `jsonReviver` - a [reviver function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse) that will be passed to `JSON.parse()` when parsing a JSON response body.
+- `jsonReplacer` - a [replacer function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify) that will be passed to `JSON.stringify()` when stringifying a JSON request body.
 
 ---
 

lib/helpers.js

@@ -24,12 +24,12 @@ function paramsHaveRequestBody(params) {
   )
 }
 
-function safeStringify (obj) {
+function safeStringify (obj, replacer) {
   var ret
   try {
-    ret = JSON.stringify(obj)
+    ret = JSON.stringify(obj, replacer)
   } catch (e) {
-    ret = jsonSafeStringify(obj)
+    ret = jsonSafeStringify(obj, replacer)
   }
   return ret
 }

request.js

@@ -1162,11 +1162,15 @@ Request.prototype.json = function (val) {
     self.setHeader('accept', 'application/json')
   }
 
+  if (typeof self.jsonReplacer === 'function') {
+    self._jsonReplacer = self.jsonReplacer
+  }
+
   self._json = true
   if (typeof val === 'boolean') {
     if (self.body !== undefined) {
       if (!/^application\/x-www-form-urlencoded\b/.test(self.getHeader('content-type'))) {
-        self.body = safeStringify(self.body)
+        self.body = safeStringify(self.body, self._jsonReplacer)
       } else {
         self.body = self._qs.rfc3986(self.body)
       }
@@ -1175,7 +1179,7 @@ Request.prototype.json = function (val) {
       }
     }
   } else {
-    self.body = safeStringify(val)
+    self.body = safeStringify(val, self._jsonReplacer)
     if (!self.hasHeader('content-type')) {
       self.setHeader('content-type', 'application/json')
     }

tests/test-json-request.js

@@ -51,6 +51,26 @@ function testJSONValueReviver(testId, value, reviver, revivedValue) {
   })
 }
 
+function testJSONValueReplacer(testId, value, replacer, replacedValue) {
+  tape('test ' + testId, function(t) {
+    var testUrl = '/' + testId
+    s.on(testUrl, server.createPostJSONValidator(replacedValue, 'application/json'))
+    var opts = {
+      method: 'PUT',
+      uri: s.url + testUrl,
+      json: true,
+      jsonReplacer: replacer,
+      body: value
+    }
+    request(opts, function (err, resp, body) {
+      t.equal(err, null)
+      t.equal(resp.statusCode, 200)
+      t.deepEqual(body, replacedValue)
+      t.end()
+    })
+  })
+}
+
 testJSONValue('jsonNull', null)
 testJSONValue('jsonTrue', true)
 testJSONValue('jsonFalse', false)
@@ -72,6 +92,15 @@ testJSONValueReviver('jsonReviver', -48269.592, function (k, v) {
 }, 48269.592)
 testJSONValueReviver('jsonReviverInvalid', -48269.592, 'invalid reviver', -48269.592)
 
+testJSONValueReplacer('jsonReplacer', -48269.592, function (k, v) {
+  return v * -1
+}, 48269.592)
+testJSONValueReplacer('jsonReplacerInvalid', -48269.592,'invalid replacer', -48269.592) 
+testJSONValueReplacer('jsonReplacerObject', {foo: 'bar'}, function (k, v) {
+  return v.toUpperCase ? v.toUpperCase() : v
+}, {foo: 'BAR'})
+
+
 tape('missing body', function (t) {
   s.on('/missing-body', function (req, res) {
     t.equal(req.headers['content-type'], undefined)