fix: deep symbol comparison

index.js

@@ -379,6 +379,11 @@ function getEnumerableKeys(target) {
   return keys;
 }
 
+function getNonEnumerableSymbols(target) {
+  var keys = Object.getOwnPropertySymbols(target);
+  return keys;
+}
+
 /*!
  * Determines if two objects have matching values, given a set of keys. Defers to deepEqual for the equality check of
  * each key. If any value of the given key is not equal, the function will return false (early).
@@ -414,6 +419,14 @@ function keysEqual(leftHandOperand, rightHandOperand, keys, options) {
 function objectEqual(leftHandOperand, rightHandOperand, options) {
   var leftHandKeys = getEnumerableKeys(leftHandOperand);
   var rightHandKeys = getEnumerableKeys(rightHandOperand);
+  var leftHandSymbols = getNonEnumerableSymbols(leftHandOperand);
+  var rightHandSymbols = getNonEnumerableSymbols(rightHandOperand);
+  if (leftHandSymbols) {
+    leftHandKeys = leftHandKeys.concat(leftHandSymbols);
+  }
+  if (rightHandSymbols) {
+    rightHandKeys = rightHandKeys.concat(rightHandSymbols);
+  }
   if (leftHandKeys.length && leftHandKeys.length === rightHandKeys.length) {
     leftHandKeys.sort();
     rightHandKeys.sort();

test/index.js

@@ -377,6 +377,48 @@ describe('Generic', function () {
 
   });
 
+  describe('Symbols', function () {
+
+    it('returns true for same symbols', function () {
+      var symb = Symbol('a');
+      var objectA = { [symb]: 'a' };
+      var objectB = { [symb]: 'a' };
+      assert(eql(objectA, objectB) === true, 'eql(obj, obj)');
+    });
+
+    it('returns false for different values', function () {
+      var symb = Symbol('a');
+      var objectA = { [symb]: 'a' };
+      var objectB = { [symb]: 'b' };
+      assert(eql(objectA, objectB) === false, 'eql(obj, obj) === false');
+    });
+
+    it('returns false for different symbols', function () {
+      var symb = Symbol('a');
+      var symb2 = Symbol('b');
+      var objectA = { [symb]: 'a' };
+      var objectB = { [symb2]: 'a' };
+      assert(eql(objectA, objectB) === false, 'eql(obj, obj) === false');
+    });
+
+    it('returns true for same nested symbols', function () {
+      var symb = Symbol('a');
+      var symb2 = Symbol('b');
+      var objectA = { [symb]: { [symb2]: 'a' } };
+      var objectB = { [symb]: { [symb2]: 'a' } };
+      assert(eql(objectA, objectB) === true, 'eql(obj, obj)');
+    });
+
+    it('returns false for different nested symbols', function () {
+      var symb = Symbol('a');
+      var symb2 = Symbol('b');
+      var objectA = { [symb]: { [symb2]: 'a' } };
+      var objectB = { [symb]: { [symb]: 'a' } };
+      assert(eql(objectA, objectB) === false, 'eql(obj, obj) === false');
+    });
+  });
+
+
   describe('errors', function () {
 
     it('returns true for same errors', function () {