NodeJS / Javascript在不同数组中查找具有相同属性的对象

Question

我在 NodeJS 中做一些事情，需要比较不同数组中的对象的重复属性。

例子：

Items = [{"id": "10", "name": "milk"},{"id":"7", "name": "banana"},{"id":"47", "name": "cheese"},{"id":"6", "name":"carrot"}]
Fridge = [{"id":"19", "name": "cheese"},{"id": "10", "name": "milk"},{"id":"43","name": "egg"}, {"id":"6", "name":"not a carrot"}]

我想获取数组中具有包含在两个数组中的属性的所有对象。 （糟糕的解释，见示例）

在这个例子中，我想得到

Output = [{"id": "10", "name": "milk"},{"id":"6", "name":"not a carrot"}]

因为只有这 2 个 ID 存在于两个输入数组中。

我该怎么做？

Answer 1

您可以将includes 方法与filter 结合使用。

Items = [{"id": "10", "name": "milk"},{"id":"7", "name": "banana"},{"id":"47", "name": "cheese"},{"id":"6", "name":"carrot"}]
Fridge = [{"id":"19", "name": "cheese"},{"id": "10", "name": "milk"},{"id":"43","name": "egg"}, {"id":"6", "name":"not a carrot"}]

result = Fridge.filter(item => Items.map(f => f.id).includes(item.id));
console.log(result);

Answer 2

您可以使用 lodash.js 轻松实现这一点，如下所示：

如果您只想检查 id：

    let Items = [{"id": "10", "name": "milk"},{"id":"7", "name": "banana"},{"id":"47", "name": "cheese"},{"id":"6", "name":"carrot"}]
let Fridge = [{"id":"19", "name": "cheese"},{"id": "10", "name": "milk"},{"id":"43","name": "egg"}, {"id":"6", "name":"not a carrot"}]

let result = _.intersectionBy(Fridge, Items, 'id');

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>

或者如果你想比较整个对象：

let Items = [{"id": "10", "name": "milk"},{"id":"7", "name": "banana"},{"id":"47", "name": "cheese"},{"id":"6", "name":"carrot"}]
let Fridge = [{"id":"19", "name": "cheese"},{"id": "10", "name": "milk"},{"id":"43","name": "egg"}, {"id":"6", "name":"not a carrot"}]

let result = _.intersectionWith(Items, Fridge, _.isEqual);

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>

`

Answer 3

另一种方法可以用于查找具有 n 个对象数组作为输入的重复项：

var Items = [{"id": "10", "name": "milk"},{"id":"7", "name": "banana"},{"id":"47", "name": "cheese"},{"id":"6", "name":"carrot"}];
var Fridge = [{"id":"19", "name": "cheese"},{"id": "10", "name": "milk"},{"id":"43","name": "egg"}, {"id":"6", "name":"not a carrot"}];

var mergedArrray = Items.concat(Fridge); //merge all
//array1 = array1.concat(array2, array3, array4, ..., arrayN);    


var duplicateIds = [];
var uniqueIds = [];

//The idea is look for the id in uniqueIds, if exist push into duplicateIds
//if not push into uniqueIds 
mergedArrray.map((obj,v)=>{
(uniqueIds.indexOf(obj.id) == -1)?uniqueIds.push(obj.id):duplicateIds.push(obj.id);
})

console.log(duplicateIds);
console.log(uniqueIds);

此解决方案不返回重复的数组，只返回引用。