我有这个小功能(在我的Angular 7应用程序内),它使用JavaScript reduce(),并在嵌套的对象数组中定位一个对象。然后,我可以继续动态更新某些属性。

现在,除了这种查找逻辑之外,我还想将对象抄入嵌套数组/从嵌套数组中抄出。

问题是:一旦找到对象,是否可以push()和/或删除对象?



const input={UID:2,GUID:"",LocationName:"USA",ParentLocation:null,subs:[{UID:42,GUID:"",LocationName:"New Jersey",Description:"",subs:[{UID:3,GUID:"",LocationName:"Essex County",ParentLocation:null,"subs":[{UID:4,LocationName:"Newark",ParentLocation:3,"subs":[{"UID":49,"GUID":"","LocationName":"Doctor Smith's Office","LocationType":{"UID":2,"LocationTypeName":"Practice","Description":"other location"},"subs":[{"HostID":38,"HostName":"Ocean Host",}]}]}]}]}]};

const findUIDObj = (uid, parent) => {
  const { UID, subs } = parent;
  if (UID === uid) {
    const { subs, ...rest } = parent;
    return rest;
  }
  if (subs) return subs.reduce((found, child) => found || findUIDObj(uid, child), null);
};
console.log(findUIDObj(49, input));

var obj = findUIDObj(49, input);
delete obj; 





例如,在我的Angular 7应用中,如果我尝试insert/delete找到的对象,它会抱怨:

前/

var obj = findUIDObj(49, input);
delete obj;

  'delete' cannot be called on an identifier in strict mode.

最佳答案

delete obj永远不会做您想要的事情:首先,它甚至不是您输入中的对象,因为该函数从找到的对象中创建了一个新对象(不包括subs属性),并返回了该对象。但更重要的是,delete用于删除属性,而不是对象。

似乎您想从其父subs属性中删除匹配的对象。为此,您将需要更改subs数组,因此它将排除匹配的对象。为了使它以通用方式工作,您的输入应为数组。否则,该根对象无法从任何内容中删除。

考虑到这一点,您的查找函数应返回在其中找到匹配项以及在哪个索引处的数组。利用这些信息,您可以决定从数组中删除该元素,或在该索引处插入另一个对象。

这是删除时的工作方式:



const input=[{UID:2,GUID:"",LocationName:"USA",ParentLocation:null,subs:[{UID:42,GUID:"",LocationName:"New Jersey",Description:"",subs:[{UID:3,GUID:"",LocationName:"Essex County",ParentLocation:null,"subs":[{UID:4,LocationName:"Newark",ParentLocation:3,"subs":[{"UID":49,"GUID":"","LocationName":"Doctor Smith's Office","LocationType":{"UID":2,"LocationTypeName":"Practice","Description":"other location"},"subs":[{"HostID":38,"HostName":"Ocean Host",}]}]}]}]}]}];

const findUIDObj = (uid, arr) => {
    if (!arr) return;
    const idx = arr.findIndex(obj => obj.UID === uid);
    if (idx > -1) return [arr, idx];
    for (const obj of arr) {
        const result = findUIDObj(uid, obj.subs);
        if (result) return result;
    }
};
console.log(findUIDObj(49, input));

const [arr, idx] = findUIDObj(49, input) || [];
if (arr) {
    arr.splice(idx, 1); // Remove object from its parent array
}

07-26 01:04
查看更多