Support null and undefined values

index.js

@@ -7,6 +7,7 @@
 
 'use strict';
 
+var defaultCompare = require('default-compare');
 var typeOf = require('kind-of');
 var get = require('get-value');
 
@@ -89,15 +90,6 @@ function compare(prop, a, b) {
   return defaultCompare(a, b);
 }
 
-/**
- * Default compare function used as a fallback
- * for sorting.
- */
-
-function defaultCompare(a, b) {
-  return a < b ? -1 : (a > b ? 1 : 0);
-}
-
 /**
  * Flatten the given array.
  */

package.json

@@ -24,8 +24,9 @@
     "test": "mocha"
   },
   "dependencies": {
-    "get-value": "^2.0.5",
-    "kind-of": "^2.0.0"
+    "default-compare": "^1.0.0",
+    "get-value": "^2.0.6",
+    "kind-of": "^5.0.2"
   },
   "devDependencies": {
     "ansi-bold": "^0.1.1",

test.js

@@ -60,6 +60,34 @@ describe('arraySort', function() {
     ]);
   });
 
+  it('should sort by a property with null values:', function() {
+    var arr = [{key: null}, {key: 'z'}, {key: 'x'}];
+    arraySort(arr, 'key').should.eql([
+      {key: 'x'},
+      {key: 'z'},
+      {key: null}
+    ]);
+  });
+
+  it('should sort by a property with undefined values:', function() {
+    var arr = [{}, {key: 'z'}, {key: 'x'}];
+    arraySort(arr, 'key').should.eql([
+      {key: 'x'},
+      {key: 'z'},
+      {}
+    ]);
+  });
+
+  it('should sort by a property with null and undefined values:', function() {
+    var arr = [{key: null}, {key: 'z'}, {}, {key: 'x'}];
+    arraySort(arr, 'key').should.eql([
+      {key: 'x'},
+      {key: 'z'},
+      {key: null},
+      {}
+    ]);
+  });
+
   it('should sort by a nested property:', function() {
     var res = arraySort(posts, 'locals.date');
     res.should.eql([
@@ -116,6 +144,84 @@ describe('arraySort', function() {
     ]);
   });
 
+  it('should sort by multiple properties with null values:', function() {
+    var posts = [
+      { foo: 'bbb', locals: { date: '2013-05-06' } },
+      { foo: 'aaa', locals: { date: '2012-01-02' } },
+      { foo: null, locals: { date: '2015-04-12' } },
+      { foo: 'ccc', locals: { date: '2014-01-02' } },
+      { foo: null, locals: { date: '2015-01-02' } },
+      { foo: 'ddd', locals: { date: '2014-01-09' } },
+      { foo: 'bbb', locals: { date: null } },
+      { foo: 'aaa', locals: { date: '2014-02-02' } },
+    ];
+
+    var actual = arraySort(posts, ['foo', 'locals.date']);
+
+    actual.should.eql([
+      { foo: 'aaa', locals: { date: '2012-01-02' } },
+      { foo: 'aaa', locals: { date: '2014-02-02' } },
+      { foo: 'bbb', locals: { date: '2013-05-06' } },
+      { foo: 'bbb', locals: { date: null } },
+      { foo: 'ccc', locals: { date: '2014-01-02' } },
+      { foo: 'ddd', locals: { date: '2014-01-09' } },
+      { foo: null, locals: { date: '2015-01-02' } },
+      { foo: null, locals: { date: '2015-04-12' } }
+    ]);
+  });
+
+  it('should sort by multiple properties with undefined values:', function() {
+    var posts = [
+      { foo: 'bbb', locals: { date: '2013-05-06' } },
+      { foo: 'aaa', locals: { date: '2012-01-02' } },
+      { locals: { date: '2015-04-12' } },
+      { foo: 'ccc', locals: { date: '2014-01-02' } },
+      { locals: { date: '2015-01-02' } },
+      { foo: 'ddd', locals: { date: '2014-01-09' } },
+      { foo: 'bbb', locals: {} },
+      { foo: 'aaa', locals: { date: '2014-02-02' } },
+    ];
+
+    var actual = arraySort(posts, ['foo', 'locals.date']);
+
+    actual.should.eql([
+      { foo: 'aaa', locals: { date: '2012-01-02' } },
+      { foo: 'aaa', locals: { date: '2014-02-02' } },
+      { foo: 'bbb', locals: { date: '2013-05-06' } },
+      { foo: 'bbb', locals: {} },
+      { foo: 'ccc', locals: { date: '2014-01-02' } },
+      { foo: 'ddd', locals: { date: '2014-01-09' } },
+      { locals: { date: '2015-01-02' } },
+      { locals: { date: '2015-04-12' } }
+    ]);
+  });
+
+  it('should sort by multiple properties with null and undefined values:', function() {
+    var posts = [
+      { foo: 'bbb', locals: { date: '2013-05-06' } },
+      { foo: 'aaa', locals: { date: null } },
+      { locals: { date: '2015-04-12' } },
+      { foo: 'ccc', locals: { date: '2014-01-02' } },
+      { locals: { date: '2015-01-02' } },
+      { foo: 'ddd', locals: { date: '2014-01-09' } },
+      { foo: null, locals: {} },
+      { foo: 'aaa', locals: { date: '2014-02-02' } },
+    ];
+
+    var actual = arraySort(posts, ['foo', 'locals.date']);
+
+    actual.should.eql([
+      { foo: 'aaa', locals: { date: '2014-02-02' } },
+      { foo: 'aaa', locals: { date: null } },
+      { foo: 'bbb', locals: { date: '2013-05-06' } },
+      { foo: 'ccc', locals: { date: '2014-01-02' } },
+      { foo: 'ddd', locals: { date: '2014-01-09' } },
+      { foo: null, locals: {} },
+      { locals: { date: '2015-01-02' } },
+      { locals: { date: '2015-04-12' } }
+    ]);
+  });
+
   it('should sort with a function:', function() {
     var arr = [{key: 'y'}, {key: 'z'}, {key: 'x'}];