[fix] Convert plus signs to spaces (#8)

Fixes #7

index.js

@@ -2,6 +2,17 @@
 
 var has = Object.prototype.hasOwnProperty;
 
+/**
+ * Decode a URI encoded string.
+ *
+ * @param {String} input The URI encoded string.
+ * @returns {String} The decoded string.
+ * @api private
+ */
+function decode(input) {
+  return decodeURIComponent(input.replace(/\+/g, ' '));
+}
+
 /**
  * Simple query string parser.
  *
@@ -21,7 +32,7 @@ function querystring(query) {
   //
   for (;
     part = parser.exec(query);
-    result[decodeURIComponent(part[1])] = decodeURIComponent(part[2])
+    result[decode(part[1])] = decode(part[2])
   );
 
   return result;

test.js

@@ -33,7 +33,7 @@ describe('querystringify', function () {
 
     it('works with object keys with empty string values', function () {
       assume(qs.stringify({ foo: '' })).equals('foo=');
-    })
+    });
 
     it('works with nulled objects', function () {
       var obj = Object.create(null);
@@ -70,6 +70,18 @@ describe('querystringify', function () {
       assume(obj.foo).equals('');
       assume(obj.bar).equals('');
       assume(obj.shizzle).equals('mynizzle');
-    })
+    });
+
+    it('decodes plus signs', function () {
+      var obj = qs.parse('foo+bar=baz+qux');
+
+      assume(obj).is.a('object');
+      assume(obj['foo bar']).equals('baz qux');
+
+      obj = qs.parse('foo+bar=baz%2Bqux');
+
+      assume(obj).is.a('object');
+      assume(obj['foo bar']).equals('baz+qux');
+    });
   });
 });