Fix: disallowCommaBeforeLineBreak correctly handle empty object

Fixes #1841
Closes gh-1846

Author: markelog

lib/rules/disallow-comma-before-line-break.js

@@ -1,7 +1,7 @@
 /**
  * Disallows commas as last token on a line in lists.
  *
- * Type: `Boolean`|`Object`
+ * Type: `Boolean`, `Object`
  *
  * Values:
  *  - `true` for default behavior (strict mode, comma on the same line)
@@ -24,7 +24,7 @@
  *     one: 1
  *     , two: 2
  * };
- * var y = { three: 3, four: 4};
+ * var y = {three: 3, four: 4};
  * ```
  *
  * ##### Invalid
@@ -87,7 +87,12 @@ module.exports.prototype = {
                 return true;
             }
 
-            return exceptFunction && node.properties.some(function(property) {
+            // See #1841
+            if (!exceptFunction || !node.properties) {
+                return false;
+            }
+
+            return node.properties.some(function(property) {
                 return property.value.type === 'FunctionExpression';
             });
         }

test/specs/rules/disallow-comma-before-line-break.js

@@ -86,6 +86,12 @@ describe('rules/disallow-comma-before-line-break', function() {
                         checker.checkString('var a = {a:1,\nc:3};').getErrorCount() === 2
                     );
                 });
+
+                it('should handle empty objects', function() {
+                    assert(
+                        checker.checkString('var x = {}\n, t = 2;').isEmpty()
+                    );
+                });
             });
         });
     });