Allow function as default value for parsing empty tags

README.md

@@ -289,7 +289,10 @@ value})``. Possible options are:
   * `normalize` (default: `false`): Trim whitespaces inside text nodes.
   * `explicitRoot` (default: `true`): Set this if you want to get the root
     node in the resulting object.
-  * `emptyTag` (default: `''`): what will the value of empty nodes be.
+  * `emptyTag` (default: `''`): what will the value of empty nodes be. In case
+  you want to use an empty object as a default value, it is better to provide a factory
+   function `() => ({})` instead. Without this function a plain object would
+  become a shared reference across all occurrences with unwanted behavior.
   * `explicitArray` (default: `true`): Always put child nodes in an array if
     true; otherwise an array is created only if there is more than one.
   * `ignoreAttrs` (default: `false`): Ignore all XML attributes and only create

src/parser.coffee

@@ -145,7 +145,10 @@ class exports.Parser extends events.EventEmitter
           obj = obj[charkey]
 
       if (isEmpty obj)
-        obj = if @options.emptyTag != '' then @options.emptyTag else emptyStr
+        if typeof @options.emptyTag == 'function'
+          obj = @options.emptyTag()
+        else
+          obj = if @options.emptyTag != '' then @options.emptyTag else emptyStr
 
       if @options.validator?
         xpath = "/" + (node["#name"] for node in stack).concat(nodeName).join("/")

test/fixtures/sample.xml

@@ -55,4 +55,7 @@
     <tagNameProcessTest/>
     <valueProcessTest>some value</valueProcessTest>
     <textordertest>this is text with <b>markup</b>   <em>like this</em> in the middle</textordertest>
+    <emptytestanother>
+
+    </emptytestanother>
 </sample>

test/parser.test.coffee

@@ -72,6 +72,11 @@ module.exports =
     # determine number of items in object
     equ Object.keys(r.sample.tagcasetest[0]).length, 3)
 
+  'test parse with empty objects and functions': skeleton({emptyTag: ()=> ({})}, (r)->
+    console.log 'Result object: ' + util.inspect r, false, 10
+    bool = r.sample.emptytestanother[0] is r.sample.emptytest[0]
+    equ bool, false)
+
   'test parse with explicitCharkey': skeleton(explicitCharkey: true, (r) ->
     console.log 'Result object: ' + util.inspect r, false, 10
     equ r.sample.chartest[0].$.desc, 'Test for CHARs'