在 Javascript 中加入 [英] Joins in Javascript

问题描述

我有 2 个对象列表:

I have 2 lists of objects:

people = 
[{id: 1, name: "Tom", carid: 1},
 {id: 2, name: "Bob", carid: 1},
 {id: 3, name: "Sir Benjamin Rogan-Josh IV", carid: 2}];

cars=
[{id: 1, name: "Ford Fiesta", color: "blue"},
 {id: 2, name: "Ferrari", color: "red"},
 {id: 3, name: "Rover 25", color: "Sunset Melting Yellow with hints of yellow"}];

是否有一个函数(可能在 Angular、JQuery、Underscore、LoDash 或其他外部库中)可以在一行中进行左连接?类似的东西:

Is there a function (possibly in Angular, JQuery, Underscore, LoDash, or other external library) to do a left join in one line on these? Something like:

peoplewithcars = leftjoin( people, cars, "carid", "id");

我可以自己编写，但如果 LoDash 有优化版本，我想使用它.

I can write my own, but if LoDash has an optimised version I'd like to use that.

推荐答案

此实现使用 ES6 展开运算符.同样，不是所要求的库函数.

This implementation uses the ES6 spread operator. Again, not a library function as asked for.

const leftJoin = (objArr1, objArr2, key1, key2) => objArr1.map(
    anObj1 => ({
        ...objArr2.find(
            anObj2 => anObj1[key1] === anObj2[key2]
        ),
        ...anObj1
    })
);

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