use JSON.stringify as default hash for all non-primitive array elements

following discussion at cujojs#32

lib/jsonPatch.js

@@ -56,9 +56,13 @@ function patchInPlace(changes, x, options) {
 }
 
 function defaultHash(x) {
-	return isValidObject(x) ? JSON.stringify(x) : x;
+	return isValidObject(x) || isArray(x) ? JSON.stringify(x) : x;
 }
 
 function isValidObject (x) {
 	return x !== null && Object.prototype.toString.call(x) === '[object Object]';
 }
+
+function isArray (x) {
+	return Object.prototype.toString.call(x) === '[object Array]';
+}

test/jiff-test.js

@@ -1,6 +1,7 @@
 var buster = require('buster');
 require('gent/test-adapter/buster');
 var assert = buster.referee.assert;
+var refute = buster.referee.refute;
 var gent = require('gent');
 var json = require('gent/generator/json');
 var deepEquals = require('../lib/deepEquals');
@@ -91,6 +92,34 @@ buster.testCase('jiff', {
 				assert.equals(patch[0].op, 'add');
 				assert(patch[0].path === '/-' || patch[0].path === '/0');
 				assert.same(patch[0].value, 1);
+			},
+			'with default hash function': {
+				'primitives as elements': {
+					'should generate an empty patch when elements are equal': function() {
+						var patch = jiff.diff([1,'a',true], [1,'a',true]);
+						assert.equals(patch.length, 0);
+					}
+				},
+				'arrays as elements': {
+					'should generate an empty patch when elements are equal': function() {
+						var patch = jiff.diff([['a'],['b'],['c']], [['a'],['b'],['c']]);
+						assert.equals(patch.length, 0);
+					}
+				},
+				'objects as elements': {
+					'object keys with consistent order': {
+						'should generate an empty patch when elements are equal': function() {
+							var patch = jiff.diff([{a:'a',b:'b',c:'c'}], [{a:'a',b:'b',c:'c'}]);
+							assert.equals(patch.length, 0);
+						}
+					},
+					'object keys with inconsistent order': {
+						'should generate a non empty patch even though elements are equal': function() {
+							var patch = jiff.diff([{b:'b',c:'c',a:'a'}], [{a:'a',b:'b',c:'c'}]);
+							refute.equals(patch.length, 0);
+						}
+					}
+				}
 			}
 		},