[Fix] use object-is to support NaN and -0 properly

Author: grahambinns

index.js

@@ -1,18 +1,22 @@
 var objectKeys = require('object-keys');
 var isArguments = require('is-arguments');
+var is = require('object-is');
 
 function deepEqual(actual, expected, options) {
   var opts = options || {};
+
   // 7.1. All identical values are equivalent, as determined by ===.
-  if (actual === expected) {
+  if (opts.strict ? is(actual, expected) : actual === expected) {
     return true;
+  }
 
-  } else if (actual instanceof Date && expected instanceof Date) {
+  if (actual instanceof Date && expected instanceof Date) {
     return actual.getTime() === expected.getTime();
+  }
 
   // 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')) {
-    return opts.strict ? actual === expected : actual == expected;
+  if (!actual || !expected || (typeof actual != 'object' && typeof expected != 'object')) {
+    return opts.strict ? is(actual, expected) : actual == expected;
   }
 
   /*

package.json

@@ -16,6 +16,7 @@
   },
   "dependencies": {
     "is-arguments": "^1.0.4",
+    "object-is": "^1.0.1",
     "object-keys": "^1.1.1"
   },
   "devDependencies": {

test/cmp.js

@@ -191,3 +191,40 @@ test('null == undefined', function (t) {
   t.notOk(equal(null, undefined, { strict: true }));
   t.end();
 });
+
+test('null == undefined', function (t) {
+  t.ok(equal(null, undefined), 'null == undefined');
+  t.ok(equal(undefined, null), 'undefined == null');
+  t.notOk(equal(null, undefined, { strict: true }), 'null !== undefined');
+  t.notOk(equal(undefined, null, { strict: true }), 'undefined !== null');
+  t.end();
+});
+
+test('NaNs', function (t) {
+  t.notOk(equal(NaN, NaN), 'NaN is not NaN');
+  t.ok(equal(NaN, NaN, { strict: true }), 'strict: NaN is NaN');
+
+  t.notOk(equal({ a: NaN }, { a: NaN }), 'two equiv objects with a NaN value are not equiv');
+  t.ok(equal({ a: NaN }, { a: NaN }, { strict: true }), 'strict: two equiv objects with a NaN value are equiv');
+
+  t.notOk(equal(NaN, 1), 'NaN !== 1');
+  t.notOk(equal(NaN, 1, { strict: true }), 'strict: NaN !== 1');
+
+  t.end();
+});
+
+test('zeroes', function (t) {
+  t.ok(equal(0, -0), '0 is -0');
+  t.ok(equal(-0, 0), '-0 is 0');
+
+  t.notOk(equal(0, -0, { strict: true }), 'strict: 0 is -0');
+  t.notOk(equal(-0, 0, { strict: true }), 'strict: -0 is 0');
+
+  t.ok(equal({ a: 0 }, { a: -0 }), 'two objects with a same-keyed 0/-0 value are equal');
+  t.ok(equal({ a: -0 }, { a: 0 }), 'two objects with a same-keyed -0/0 value are equal');
+
+  t.notOk(equal({ a: 0 }, { a: -0 }, { strict: true }), 'strict: two objects with a same-keyed 0/-0 value are equal');
+  t.notOk(equal({ a: -0 }, { a: 0 }, { strict: true }), 'strict: two objects with a same-keyed -0/0 value are equal');
+
+  t.end();
+});