将2个对象数组与Underscore进行比较,以找出差异

Question

我有2个数组,一个是newVal,另一个是origVal define

原稿:

[
{"ListingId":1762276,"Rating":3,"ListPrice":7411828,"PropertyType":"Residential"},
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"},
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"},
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"},
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"},
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"}
]

新:

[
{"ListingId":1762276,"Rating":2,"ListPrice":7411828,"PropertyType":"Residential"},
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"},
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"},
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"},
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"},
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"}
]

如果我更改了new中的一个评级,我如何检测到该更改,并检索更改的对象？

虽然我认为不重要,但一次只会有一个变化.

仅供参考:这些阵列是从Anjularjs手表集中制作的

$scope.$watchCollection('items', function (new, old) {

}, true); 

谢谢你,斯蒂芬

Answer 1

看看这个:

var a = [
{"ListingId":1762276,"Rating":3,"ListPrice":7411828,"PropertyType":"Residential"},
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"},
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"},
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"},
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"},
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"}
];

var b = [
{"ListingId":1762276,"Rating":2,"ListPrice":7411828,"PropertyType":"Residential"},
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"},
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"},
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"},
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"},
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"}
]

var difference = function(array){
   var rest = Array.prototype.concat.apply(Array.prototype, Array.prototype.slice.call(arguments, 1));

   var containsEquals = function(obj, target) {
    if (obj == null) return false;
    return _.any(obj, function(value) {
      return _.isEqual(value, target);
    });
  };

  return _.filter(array, function(value){ return ! containsEquals(rest, value); });
};

console.log(JSON.stringify(difference(b, a)));
> [{"ListingId":1762276,"Rating":2,"ListPrice":7411828,"PropertyType":"Residential"}]

代码基于与下划线的原始函数差异,但它使用isEqual执行对象之间的深度比较.