Javascript 比较带有下划线的两个对象数组以找出差异

我有两个数组，一个是newVal，另一个是origVal define

原文：

新的：

如果我在new中更改了一个评级，我如何检测该更改并检索更改的对象

一次只会有一个变化，尽管我认为这并不重要

仅供参考：这些阵列由Anjularjs watchcollection生产

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

}, true); 

谢谢,，

---

Stephen

如果顺序不变，只需简单的迭代即可。下划线为此任务提供了以下选项：

var changedObj = _.find(newVal, function(obj, index) {
    return obj.Rating != oldVal[index].Rating;
});

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"}]

代码基于下划线中的原始函数，但它使用以下命令在对象之间执行深度比较。

如何：

const current = [{name:'a'},{name:'b'},{name:'c'}]
const update = [{name:'x'},{name:'a'},{name:'b'},{name:'f'}]
const records = current.concat(update);
const diff = {};
diff.in = []
diff.out = [];
records.forEach(item => {
  if(!current.find(cur => item.name == cur.name))diff.in.push(item)
  if(!update.find(up => item.name == up.name ))diff.out.push(item)
})

---

基于@Jonathan的答案，我修改了一个版本，该版本返回一个可用的差异列表，包括哪一方有差异以及记录的索引

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":1832131,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"},
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"},
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"}
]

function diff(arr1, arr2){
    var aDiffs=[]
    function __comp(arrL, arrR, side){
        var rL, rR, bFound
        for(var i=0;i<arrL.length;i++){rL=arrL[i]
            bFound=false
            for(var j=0;j<arrR.length;j++){rR=arrR[j]
                if (_.isEqual(rL, rR)){ 
                    bFound=true
                    break
                }
            }
            if (!bFound)aDiffs.push({side: side, ind: i, obj: rL})
        }
    }
    __comp(arr1, arr2, 'l')
    __comp(arr2, arr1, 'r')
    return aDiffs
};


console.log(JSON.stringify(diff(b, a)).replace(/},{/g, "}\n,{"));

---

这些对象是数组中的相同对象（即

==

标识）还是外观相似？您需要什么结果？数组中更改对象的索引，新更改对象，旧更改对象，评级？我更喜欢更改对象{“ListingId”：1762276，“评级”：2，“ListPrice”：7411828，“PropertyType:“Residential”}它太棒了，它能做什么。我希望我能理解代码。

const current = [{name:'a'},{name:'b'},{name:'c'}]
const update = [{name:'x'},{name:'a'},{name:'b'},{name:'f'}]
const records = current.concat(update);
const diff = {};
diff.in = []
diff.out = [];
records.forEach(item => {
  if(!current.find(cur => item.name == cur.name))diff.in.push(item)
  if(!update.find(up => item.name == up.name ))diff.out.push(item)
})

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":1832131,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"},
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"},
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"}
]

function diff(arr1, arr2){
    var aDiffs=[]
    function __comp(arrL, arrR, side){
        var rL, rR, bFound
        for(var i=0;i<arrL.length;i++){rL=arrL[i]
            bFound=false
            for(var j=0;j<arrR.length;j++){rR=arrR[j]
                if (_.isEqual(rL, rR)){ 
                    bFound=true
                    break
                }
            }
            if (!bFound)aDiffs.push({side: side, ind: i, obj: rL})
        }
    }
    __comp(arr1, arr2, 'l')
    __comp(arr2, arr1, 'r')
    return aDiffs
};


console.log(JSON.stringify(diff(b, a)).replace(/},{/g, "}\n,{"));

[{"side":"l","ind":0,"obj":{"ListingId":1762276,"Rating":2,"ListPrice":7411828,"PropertyType":"Residential"}}
,{"side":"l","ind":3,"obj":{"ListingId":1832131,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"}}
,{"side":"r","ind":0,"obj":{"ListingId":1762276,"Rating":3,"ListPrice":7411828,"PropertyType":"Residential"}}
,{"side":"r","ind":3,"obj":{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"}}]