Fix #554 is empty with Symbol as property name (#555)

Author: ginoemiliozzi

packages/object-is-empty/index.cjs

@@ -39,7 +39,7 @@ function isEmpty(obj) {
   var type = {}.toString.call(obj);
 
   if (type == '[object Object]') {
-    return !Object.keys(obj).length;
+    return !Object.keys(obj).length && !Object.getOwnPropertySymbols(obj).length;
   }
 
   if (type == '[object Map]' || type == '[object Set]') {

packages/object-is-empty/index.mjs

@@ -39,7 +39,7 @@ function isEmpty(obj) {
   var type = {}.toString.call(obj);
 
   if (type == '[object Object]') {
-    return !Object.keys(obj).length;
+    return !Object.keys(obj).length && !Object.getOwnPropertySymbols(obj).length;
   }
 
   if (type == '[object Map]' || type == '[object Set]') {

test/object-is-empty/index.cjs

@@ -13,8 +13,9 @@ test('empty object, array, map or set', function(t) {
 });
 
 test('non-empty object, array, map or set', function(t) {
-  t.plan(6);
+  t.plan(7);
   t.notOk(isEmpty({a: 3, b: 5}));
+  t.notOk(isEmpty({[Symbol('a')]: "some-value"}));
   t.notOk(isEmpty([1, 2]));
   t.notOk(isEmpty(['a', 'b']));
   t.notOk(isEmpty(new Array(4)));