Fix stack trace for strict json parse error

HISTORY.md

@@ -1,6 +1,7 @@
 unreleased
 ==========
 
+  * Fix stack trace for strict json parse error
   * deps: depd@~1.1.2
     - perf: remove argument reassignment
   * deps: http-errors@~1.6.3

lib/types/json.js

@@ -89,6 +89,7 @@ function json (options) {
       return JSON.parse(body, reviver)
     } catch (e) {
       throw normalizeJsonSyntaxError(e, {
+        message: e.message,
         stack: e.stack
       })
     }
@@ -208,12 +209,9 @@ function normalizeJsonSyntaxError (error, obj) {
     }
   }
 
-  var props = Object.keys(obj)
-
-  for (var j = 0; j < props.length; j++) {
-    var prop = props[j]
-    error[prop] = obj[prop]
-  }
+  // replace stack before message for Node.js 0.10 and below
+  error.stack = obj.stack.replace(error.message, obj.message)
+  error.message = obj.message
 
   return error
 }

test/json.js

@@ -273,6 +273,17 @@ describe('bodyParser.json()', function () {
           .send('true')
           .expect(400, 'entity.parse.failed', done)
       })
+
+      it('should include correct message in stack trace', function (done) {
+        request(this.server)
+          .post('/')
+          .set('Content-Type', 'application/json')
+          .set('X-Error-Property', 'stack')
+          .send('true')
+          .expect(400)
+          .expect(shouldContainInBody(parseError('#rue').replace('#', 't')))
+          .end(done)
+      })
     })
   })
 
@@ -639,3 +650,10 @@ function parseError (str) {
     return e.message
   }
 }
+
+function shouldContainInBody (str) {
+  return function (res) {
+    assert.ok(res.text.indexOf(str) !== -1,
+      'expected \'' + res.text + '\' to contain \'' + str + '\'')
+  }
+}