Javascript 如何在 React 中深度克隆对象？
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How do I deep clone an object in React?
提问by SpaceDogCS
let oldMessages = Object.assign({}, this.state.messages);
// this.state.messages[0].id = 718
console.log(oldMessages[0].id);
// Prints 718
oldMessages[0].id = 123;
console.log(this.state.messages[0].id);
// Prints 123
How can I prevent oldMessagesto be a reference, I want to change the value of oldMessageswithout changing the value of state.messages
我怎样才能防止oldMessages被引用，我想改变的值oldMessages而不改变的值state.messages
回答by AryanJ-NYC
You need to make a deep copy. Lodash's cloneDeepmakes this easy:
你需要做一个深拷贝。Lodash 的 cloneDeep使这变得简单：
import cloneDeep from 'lodash/cloneDeep';
const oldMessages = cloneDeep(this.state.messages);
oldMessages[0].id = 123;
Good luck!
祝你好运！
回答by Anjali
Try Using
尝试使用
let tempVar = JSON.parse(JSON.stringify(this.state.statename))
回答by Hozefa
One of the best ways to deep clone objects is using the spreadoperator. It does deep cloning without us having to write any extra code.
深度克隆对象的最佳方法之一是使用spread运算符。它可以进行深度克隆，而无需我们编写任何额外的代码。
For example...
例如...
const obj1 = {foo: {baz: 'bar'}}
const obj2 = {test: 'temp}
const obj3 = {...obj1, ...obj2}
// obj3 = {foo: {baz: 'bar'}, test: 'temp}
