From 746ef032f7c7d49f02aed2fff45412f61fd15e8e Mon Sep 17 00:00:00 2001
From: Nate Silva <nate@natesilva.com>
Date: Wed, 19 Jun 2019 13:03:29 -0700
Subject: [PATCH 1/3] failing test for symbol keys

---
 test/merge.js | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/test/merge.js b/test/merge.js
index 21a68e2..27a3f9b 100644
--- a/test/merge.js
+++ b/test/merge.js
@@ -614,3 +614,14 @@ test('should merge correctly if custom merge is not a valid function', function(
 	t.end()
 
 })
+
+test('add symbol keys in target that do not exist at the root', function(t) {
+    var mySymbol = Symbol();
+	var src = { [mySymbol]: 'value1' }
+	var target = {}
+
+	var res = merge(target, src)
+
+	t.deepEqual(Object.getOwnPropertySymbols(res), Object.getOwnPropertySymbols(src))
+	t.end()
+})

From 8d53ab94e313fc1a739f547e4573cd30e280890a Mon Sep 17 00:00:00 2001
From: Nate Silva <nate@natesilva.com>
Date: Wed, 19 Jun 2019 13:12:45 -0700
Subject: [PATCH 2/3] Support properties that have Symbol keys

---
 index.js | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/index.js b/index.js
index dfc9b14..e9570a3 100644
--- a/index.js
+++ b/index.js
@@ -24,14 +24,20 @@ function getMergeFunction(key, options) {
 	return typeof customMerge === 'function' ? customMerge : deepmerge
 }
 
+function getKeys(target) {
+    return Object.getOwnPropertySymbols ?
+        Object.keys(target).concat(Object.getOwnPropertySymbols(target))
+        : Object.keys(target)
+}
+
 function mergeObject(target, source, options) {
 	var destination = {}
 	if (options.isMergeableObject(target)) {
-		Object.keys(target).forEach(function(key) {
+		getKeys(target).forEach(function(key) {
 			destination[key] = cloneUnlessOtherwiseSpecified(target[key], options)
 		})
 	}
-	Object.keys(source).forEach(function(key) {
+	getKeys(source).forEach(function(key) {
 		if (!options.isMergeableObject(source[key]) || !target[key]) {
 			destination[key] = cloneUnlessOtherwiseSpecified(source[key], options)
 		} else {

From 2f0e45a3b2d44c4cc33caa302e3e5f92bd022f98 Mon Sep 17 00:00:00 2001
From: Nate Silva <nate@natesilva.com>
Date: Wed, 19 Jun 2019 18:04:02 -0700
Subject: [PATCH 3/3] Limit to enumerable symbols

This parallels Object.keys, which only returns enumerable names.
---
 index.js | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/index.js b/index.js
index e9570a3..f850262 100644
--- a/index.js
+++ b/index.js
@@ -24,10 +24,16 @@ function getMergeFunction(key, options) {
 	return typeof customMerge === 'function' ? customMerge : deepmerge
 }
 
-function getKeys(target) {
+function getEnumerableOwnPropertySymbols(target) {
     return Object.getOwnPropertySymbols ?
-        Object.keys(target).concat(Object.getOwnPropertySymbols(target))
-        : Object.keys(target)
+        Object.getOwnPropertySymbols(target).filter(function(symbol) {
+            return target.propertyIsEnumerable(symbol)
+        })
+        : [];
+}
+
+function getKeys(target) {
+    return Object.keys(target).concat(getEnumerableOwnPropertySymbols(target))
 }
 
 function mergeObject(target, source, options) {