Serialize: Treat literal and function-returned null/undefined the same

Fixes gh-3005

Closes gh-3007

2 files changed, 8 insertions, 2 deletions

diff --git a/src/serialize.js b/src/serialize.js
index a0b948460..9a735fec1 100644
--- a/src/serialize.js
+++ b/src/serialize.js
@@ -58,7 +58,10 @@ jQuery.param = function( a, traditional ) {
 		add = function( key, value ) {
 
 			// If value is a function, invoke it and return its value
-			value = jQuery.isFunction( value ) ? value() : ( value == null ? "" : value );
+			value = jQuery.isFunction( value ) ? value() : value;
+			if ( value == null ) {
+				value = "";
+			}
 			s[ s.length ] = encodeURIComponent( key ) + "=" + encodeURIComponent( value );
 		};
 
diff --git a/test/unit/serialize.js b/test/unit/serialize.js
index 65d94171c..b87a0aa85 100644
--- a/test/unit/serialize.js
+++ b/test/unit/serialize.js
@@ -1,7 +1,7 @@
 QUnit.module( "serialize", { teardown: moduleTeardown } );
 
 QUnit.test( "jQuery.param()", function( assert ) {
-	assert.expect( 23 );
+	assert.expect( 24 );
 
 	var params, settings;
 
@@ -74,6 +74,9 @@ QUnit.test( "jQuery.param()", function( assert ) {
 	params = { "param1": null };
 	assert.equal( jQuery.param( params, false ), "param1=", "Make sure that null params aren't traversed." );
 
+	params = { "param1": function() {}, "param2": function() { return null; } };
+	assert.equal( jQuery.param( params, false ), "param1=&param2=", "object with function property that returns null value" );
+
 	params = { "test": { "length": 3, "foo": "bar" } };
 	assert.equal( jQuery.param( params, false ), "test%5Blength%5D=3&test%5Bfoo%5D=bar", "Sub-object with a length property" );