It is not possible to send a date object as extra, closes #8

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false

README.md

@@ -8,7 +8,7 @@ The Graylog Extended Log Format. Pro - because of code-quality.
 ## Installation
 ```
 "dependencies": {
-  "gelf-pro": "~0.5"
+  "gelf-pro": "~0.6"
 }
 ```
 ```npm install gelf-pro```
@@ -47,6 +47,18 @@ log.info('Oooops.', new Error('An error message'));
 log.info(new Error('An error message'));
 ```
 
+##### Extra
+In case `extra` [is a plain object](https://lodash.com/docs#isPlainObject),
+the library converts it to a readable format. Other values [are converted to string](https://lodash.com/docs#toString).
+```javascript
+log.message(
+  'a new msg goes here',
+  {me: {fname: 'k', lname: 'k', bdate: new Date(2000, 01, 01)}}
+);
+// the extra becomes:
+// {_me_fname: 'k', _me_lname: 'k', _me_bdate: 'Tue Feb 01 2000 00:00:00 GMT+0100 (CET)'}
+``` 
+
 ##### Filtering
 Sometimes we have to discard a message which is not suitable for the current environment.
 It is not possible to modify the data.

lib/gelf-pro.js

@@ -87,10 +87,10 @@ gelf.getStringFromObject = function (obj) {
       if ((/[^\w]/).test(key)) {
         console.warn(key + ': the key format is not valid');
       }
-      if (_.isObject(value)) {
+      if (_.isPlainObject(value)) {
         return recursion(value, prefix ? [prefix, key].join('_') : key);
       }
-      result[(prefix ? [null, prefix, key] : [null, key]).join('_')] = value;
+      result[(prefix ? [null, prefix, key] : [null, key]).join('_')] = _.toString(value);
     });
   };
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gelf-pro",
-  "version": "0.5.1",
+  "version": "0.6.0",
   "main": "./lib/gelf-pro.js",
   "author": "Kanstantsin Kamkou <[email protected]>",
   "description": "The Graylog Extended Log Format for the Node.js",

test/tests.js

@@ -107,6 +107,12 @@ module.exports = {
       result.should.have.property('_level1_level2_level3_value3').equal('value3');
     },
 
+    'Work with dates': function () {
+      var gelf = _.cloneDeep(gelfOriginal),
+        date = new Date();
+      JSON.parse(gelf.getStringFromObject({test: date}))._test.should.equal(date.toString());
+    },
+
     'Transform an Error object': function () {
       var gelf = _.cloneDeep(gelfOriginal),
         err = new Error('Some error message');
@@ -147,7 +153,7 @@ module.exports = {
         bytes.should.be.equal(0);
         stub.lastCall.args.should.eql([{short_message: 'test', level: 4}]);
         spyFn.lastCall.returned(false).should.be.true();
-        spySend.neverCalledWith().should.be.true();;
+        spySend.neverCalledWith().should.be.true();
         done();
       });
     }