Use separate 'createJSON' method that can be overriden

Author: rubenstolk

lib/response.js

@@ -193,6 +193,25 @@ res.send = function send(body) {
   return this;
 };
 
+/**
+ * Create JSON response.
+ *
+ * Examples:
+ *
+ *     res.json(null);
+ *     res.json({ user: 'tj' });
+ *
+ * @param {string|number|boolean|object} obj
+ * @api public
+ */
+res.createJSON = function createJSON(obj) {
+  var app = this.app;
+  var replacer = app.get('json replacer');
+  var spaces = app.get('json spaces');
+  var body = JSON.stringify(obj, replacer, spaces);
+  return body;
+};
+
 /**
  * Send JSON response.
  *
@@ -221,11 +240,8 @@ res.json = function json(obj) {
     }
   }
 
-  // settings
-  var app = this.app;
-  var replacer = typeof res.jsonReplacer !== 'undefined' ? res.jsonReplacer : app.get('json replacer');
-  var spaces = app.get('json spaces');
-  var body = JSON.stringify(val, replacer, spaces);
+  // json
+  var body = this.createJSON(val);
 
   // content-type
   if (!this.get('Content-Type')) {
@@ -264,14 +280,8 @@ res.jsonp = function jsonp(obj) {
   }
 
   // settings
-  var app = this.app;
-  var replacer = res.get('json replacer');
-  if (typeof replacer === 'undefined') {
-    replacer = app.get('json replacer');
-  }
-  var spaces = app.get('json spaces');
-  var body = JSON.stringify(val, replacer, spaces);
-  var callback = this.req.query[app.get('jsonp callback name')];
+  var body = this.createJSON(val);
+  var callback = this.req.query[this.app.get('jsonp callback name')];
 
   // content-type
   if (!this.get('Content-Type')) {