克隆Javascript/Typescript中的数组 [英] Cloning an array in Javascript/Typescript
问题描述
我有两个对象组成的数组:
I have array of two objects:
genericItems: Item[] = [];
backupData: Item[] = [];
我正在用genericItems
数据填充HTML表.该表是可修改的.有一个重置按钮可以撤消使用backUpData
完成的所有更改.此数组由服务填充:
I am populating my HTML table with genericItems
data. The table is modifiable. There is a reset button to undo all changes done with backUpData
. This array is populated by a service:
getGenericItems(selected: Item) {
this.itemService.getGenericItems(selected).subscribe(
result => {
this.genericItems = result;
});
this.backupData = this.genericItems.slice();
}
我的想法是,用户更改将反映在第一个阵列中,而第二个阵列可以用作重置操作的备份.我在这里面临的问题是用户修改表时(genericItems[])
第二个数组backupData
也被修改了.
My idea was that, the user changes will get reflected in first array and second array can be used as backup for reset operation. The issue I am facing here is when the user modifies the table (genericItems[])
the second array backupData
also gets modified.
这是怎么回事,如何预防呢?
How is this happening and how to prevent this?
推荐答案
尝试一下:
克隆对象:
const myClonedObject = Object.assign({}, myObject);
克隆数组:
选项1-如果您具有原始类型的数组:
Option 1 - if you have an array of primitive types:
const myClonedArray = Object.assign([], myArray);
选项2-如果您有对象数组:(感谢@mumblesNZ)
Option 2 - if you have an array of objects: (thanks @mumblesNZ)
const myArray= [{ a: 'a', b: 'b' }, { a: 'c', b: 'd' }];
const myClonedArray = [];
myArray.forEach(val => myClonedArray.push(Object.assign({}, val)));
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