Question

我有一个父数组，我正在从父数组中获取一个经过过滤的数组（子数组）。在更改子数组时，我的父数组也在更改。请您帮我如何保持相同的父数组不变。< / p>

SELECT

Answer 1

filter()不会复制对象。它只是为您提供了一个新数组，其中引用了parentArray中完全相同的对象。

如果要在childArray中进行复印，则需要自己完成。一种实现方法是将map()与Object.assign()一起使用，这将为您的对象创建浅表副本：

let parentArray=[
    { "id":"1", "Package":"Tes1", "Version":"20080210-1.1", "Maintainer":"Stefano Canepa"},
    { "id":"1", "Package":"Test2", "Version":"7.0-1", "Maintainer":"Debian Games Team"},
    { "id":"1", "Package":"Test3", "Version":"20080210-1.1", "Maintainer":"Stefano Canepa"},
    { "id":"1", "Package":"Test4", "Version":"7.0-1", "Maintainer":"Debian Games Team"},
    { "id":"5", "Package":"Tdst5", "Version":"20080210-1.1", "Maintainer":"Stefano Canepa"},
    { "id":"6", "Package":"Test6", "Version":"7.0-1", "Maintainer":"Debian Games Team"},
    { "id":"7", "Package":"Test7", "Version":"20080210-1.1", "Maintainer":"Stefano Canepa"},
    { "id":"8", "Package":"Test8", "Version":"7.0-1", "Maintainer":"Debian Games Team"}
  ];
 
 let childArray=parentArray.filter(x=>x.id=="1")
      .map(obj => Object.assign({}, obj))  // make copies
      
 console.log("before"+JSON.stringify(parentArray));
 childArray.forEach(value=>value.Package="changed")
 console.log("after"+JSON.stringify(parentArray));

Javascript->迭代for循环.Child变量中的更改更改了父变量

1 个答案: