fixed prototype comparison

index.js

@@ -11,6 +11,16 @@ var deepEqual = module.exports = function (actual, expected, opts) {
   } else if (actual instanceof Date && expected instanceof Date) {
     return actual.getTime() === expected.getTime();
 
+  // 7.3 If the expected value is a RegExp object, the actual value is
+  // equivalent if it is also a RegExp object with the same source and
+  // properties (`global`, `multiline`, `lastIndex`, `ignoreCase`).
+  } else if (actual instanceof RegExp && expected instanceof RegExp) {
+    return actual.source === expected.source &&
+           actual.global === expected.global &&
+           actual.multiline === expected.multiline &&
+           actual.lastIndex === expected.lastIndex &&
+           actual.ignoreCase === expected.ignoreCase;
+
   // 7.3. Other pairs that do not both pass typeof value == 'object',
   // equivalence is determined by ==.
   } else if (!actual || !expected || typeof actual != 'object' && typeof expected != 'object') {
@@ -42,10 +52,21 @@ function isBuffer (x) {
 
 function objEquiv(a, b, opts) {
   var i, key;
+
   if (isUndefinedOrNull(a) || isUndefinedOrNull(b))
     return false;
+
+  var abc = 5;
+  try {
+    Object.getPrototypeOf(abc);  // all ok ES6
+  } catch (e) {  // error ES5
+    Object.getPrototypeOf = function(obj) {
+        return obj.__proto__;
+    }
+  }
+
   // an identical 'prototype' property.
-  if (a.prototype !== b.prototype) return false;
+  if (Object.getPrototypeOf(a) !== Object.getPrototypeOf(b)) return false;
   //~~~I've managed to break Object.keys through screwy arguments passing.
   //   Converting to array solves the problem.
   if (isArguments(a)) {

test/cmp.js

@@ -59,7 +59,7 @@ test('arguments class', function (t) {
 test('test the arguments shim', function (t) {
     t.ok(isArguments.supported((function(){return arguments})()));
     t.notOk(isArguments.supported([1,2,3]));
-    
+
     t.ok(isArguments.unsupported((function(){return arguments})()));
     t.notOk(isArguments.unsupported([1,2,3]));
 
@@ -93,3 +93,20 @@ test('null == undefined', function (t) {
     t.notOk(equal(null, undefined, { strict: true }))
     t.end()
 })
+
+test('test objects', function (t) {
+    var d = new Date(1387585278000);
+    var e = new RegExp("abc");
+    t.notOk(equal(d, e));
+    t.end();
+});
+
+test('test RegExp !=', function (t) {
+    t.notOk(equal(/abc/, /xyz/));
+    t.end();
+});
+
+test('test RegExp ==', function (t) {
+    t.ok(equal(/abc/, /abc/));
+    t.end();
+});