Support enumerable symbol properties in merge()

Author: kanongil

lib/index.js

@@ -126,10 +126,12 @@ exports.merge = function (target, source, isNullOverride /* = true */, isMergeAr
         return target;
     }
 
-    const keys = Object.keys(source);
+    const keys = Reflect.ownKeys(source);
     for (let i = 0; i < keys.length; ++i) {
         const key = keys[i];
-        if (key === '__proto__') {
+        if (key === '__proto__' ||
+            !Object.prototype.propertyIsEnumerable.call(source, key)) {
+
             continue;
         }
 

test/index.js

@@ -617,6 +617,15 @@ describe('merge()', () => {
         expect(a.x).to.equal(/test/);
     });
 
+    it('overrides Symbol properties', () => {
+
+        const sym = Symbol();
+        const a = { [sym]: 1 };
+
+        Hoek.merge({ [sym]: {} }, a);
+        expect(a[sym]).to.equal(1);
+    });
+
     it('skips __proto__', () => {
 
         const a = '{ "ok": "value", "__proto__": { "test": "value" } }';