比较数组对象并显示差异 [英] Compare array objects and show difference

问题描述

我有两个要比较的数组，并检查其中一个数组中是否有删除的项目。如果有显示差异（已删除项目）

I have two arrays which I want to compare and check if there is an deleted item in one of these arrays. If there is show me the difference (deleted item)

以下是我想要实现此目标的代码：

Here is the code below how I would like to achieve this:

 var completedList = [{id:1},{id:2},{id:3},{id:4},{id:7},{id:8}];
    var invalidList = [{id:3},{id:4},{id:5},{id:6}];

    // filter the items from the invalid list, out of the complete list
    var validList = completedList.map((item) => {
        console.log(item.id)
        return item.id;
        //console.log(invalidList.id);
    }).filter(item => {
        Object.keys(invalidList).map(key => {
            console.log(invalidList[key].id)
            //return !invalidList[key].id.includes(item.id);
        });
    })

    console.log(validList); // Print [1,2,7,8]

    // get a Set of the distinct, valid items
    var validItems = new Set(validList);

但这会给我带来很多 id的我如何映射数组和过滤器对象属性id？并且只显示这些数组对象之间的区别。

But this returns me a lot of id's how can I map through both array's and filter on object property id? And only show the difference between these array objects.

所以基本上我期望看到这些数组之间的差异所以记录id的差异所以在这个例子中： code> 1,2,5,6,7,8

So basically what I expect is to see the difference between those arrays so log the differences in id's so in this example: 1,2,5,6,7,8

推荐答案

你可以参加 Set 获得差异。为了获得彼此之间的差异（对称差异），您需要获得两者之间的差异。

You could take a Set for getting a difference. For getting the differences from each other (a symmetric difference), you need to get both differences.

const
    difference = (a, b) => Array.from(b.reduce((s, v) => (s.delete(v), s), new Set(a))),
    getId = ({ id }) => id;

var completedList = [{ id: 1 }, { id: 2 }, { id: 3 }, { id: 4 }, { id: 7 }, { id: 8 }],
    invalidList = [{ id: 3 }, { id: 4 }, { id: 5 }, { id: 6 }],
    complete = completedList.map(getId),
    invalid = invalidList.map(getId),
    left = difference(complete, invalid),
    right = difference(invalid, complete),
    result = [...left, ...right]

console.log(result.join(' '));
console.log(left.join(' '));
console.log(right.join(' '));

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