将2个对象数组与Underscore进行比较，以找出差异 [英] Compare 2 arrays of objects with Underscore to find the differnce

问题描述

我有2个数组，一个是newVal，另一个是origVal define

I have 2 arrays, one is newVal and the other is origVal define

orig：

[
{"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"}
]

new：

[
{"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？

If I change one of the ratings in new, how might I detect that change, and retrieve the changed object?

一次只会有一次更改，但我认为不重要。

There will only be one change at a time, although I don't think that matters.

FYI ：这些数组是从Anjularjs watchcollection生成的

FYI: These arrays are being produced from an Anjularjs watchcollection

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

}, true); 

谢谢你，
Stephen

Thank you, Stephen

推荐答案

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"}]

该代码基于原始函数与下划线的差异，但它执行的是使用 isEqual 对对象进行深入比较。

The code is based on the original function difference from underscore, but it performs a deep comparison between objects using isEqual.

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