不变违规：对象作为React子元素无效

本文翻译自：Invariant Violation: Objects are not valid as a React child

In my component's render function I have: 在组件的render函数中，我有：

render() {
    const items = ['EN', 'IT', 'FR', 'GR', 'RU'].map((item) => {
      return (
{item}
);
    });
    return (
      

        ...
                

                  {items}
                
         ...
      
    );
  }

everything renders fine, however when clicking the

element I receive the following error: 一切正常，但是单击

元素时，出现以下错误：

Uncaught Error: Invariant Violation: Objects are not valid as a React child (found: object with keys {dispatchConfig, dispatchMarker, nativeEvent, target, currentTarget, type, eventPhase, bubbles, cancelable, timeStamp, defaultPrevented, isTrusted, view, detail, screenX, screenY, clientX, clientY, ctrlKey, shiftKey, altKey, metaKey, getModifierState, button, buttons, relatedTarget, pageX, pageY, isDefaultPrevented, isPropagationStopped, _dispatchListeners, _dispatchIDs}). 未捕获的错误：始终违反：对象作为React子对象无效（找到：带有键{dispatchConfig，dispatchMarker，nativeEvent，target，currentTarget，type，eventPhase，气泡，cancelable，timeStamp，defaultPrevented，isTrusted，视图，详细信息，screenX的对象，screenY，clientX，clientY，ctrlKey，shiftKey，altKey，metaKey，getModifierState，按钮，按钮，relatedTarget，pageX，pageY，isDefaultPrevented，isPropagationStopped，_dispatchListeners，_dispatchIDs}）。 If you meant to render a collection of children, use an array instead or wrap the object using createFragment(object) from the React add-ons. 如果您打算渲染孩子的集合，请改用数组或使用React附加组件中的createFragment（object）包装对象。 Check the render method of Welcome . 检查Welcome的渲染方法。

If I change to this.onItemClick.bind(this, item) to (e) => onItemClick(e, item) inside the map function everything works as expected. 如果我将map函数内的this.onItemClick.bind(this, item)更改为(e) => onItemClick(e, item) ，一切都会按预期进行。

If someone could explain what I am doing wrong and explain why do I get this error, would be great 如果有人可以解释我在做什么错并解释为什么我会收到此错误，那将是很好的

UPDATE 1: 更新1：
onItemClick function is as follows and removing this.setState results in error disappearing. onItemClick函数如下，删除this.setState导致错误消失。

onItemClick(e, item) {
    this.setState({
      lang: item,
    });
}

But I cannot remove this line as I need to update state of this component 但是我无法删除此行，因为我需要更新此组件的状态

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#1楼

参考：https://stackoom.com/question/2eXmp/不变违规-对象作为React子元素无效

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#2楼

I was having this error and it turned out to be that I was unintentionally including an Object in my JSX code that I had expected to be a string value: 我遇到了这个错误，结果是我无意中在我的JSX代码中包含了一个我期望是字符串值的对象：

return (
    
        {breadcrumbElement}
    
)

breadcrumbElement used to be a string but due to a refactor had become an Object. breadcrumbElement曾经是一个字符串，但是由于重构而成为对象。 Unfortunately, React's error message didn't do a good job in pointing me to the line where the problem existed. 不幸的是，React的错误消息不能很好地指出问题所在。 I had to follow my stack trace all the way back up until I recognized the "props" being passed into a component and then I found the offending code. 我必须一直跟踪堆栈跟踪，直到我意识到“ props”已传递到组件中，然后才发现有问题的代码。

You'll need to either reference a property of the object that is a string value or convert the Object to a string representation that is desirable. 您将需要引用对象的属性（它是字符串值），或者将Object转换为所需的字符串表示形式。 One option might be JSON.stringify if you actually want to see the contents of the Object. 如果您确实想查看Object的内容，则一个选项可能是JSON.stringify 。

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#3楼

So I got this error when trying to display the createdAt property which is a Date object. 因此，当尝试显示createdAt对象为Date对象时出现了此错误。 If you concatenate .toString() on the end like this, it will do the conversion and eliminate the error. 如果像这样在最后连接.toString() ，它将进行转换并消除错误。 Just posting this as a possible answer in case anyone else ran into the same problem: 只是将其作为可能的答案发布，以防其他人遇到相同的问题：

{this.props.task.createdAt.toString()}

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#4楼

I just got the same error but due to a different mistake: I used double braces like: 我只是遇到了相同的错误，但是由于一个不同的错误：我使用了像这样的双括号：

{{count}}

to insert the value of count instead of the correct: 插入count的值而不是正确的值：

{count}

which the compiler presumably turned into {{count: count}} , ie trying to insert an Object as a React child. 编译器大概变成了{{count: count}} ，即试图插入一个对象作为React子对象。

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#5楼

Just thought I would add to this as I had the same problem today, turns out that it was because I was returning just the function, when I wrapped it in a

tag it started working, as below 只是以为我会加上这个问题，因为今天我遇到了同样的问题，结果是因为我只返回了函数，所以当我将其包装在

标记中时，它开始工作，如下所示

renderGallery() {
  const gallerySection = galleries.map((gallery, i) => {
    return (
      

        ...
      
    );
  });
  return (
    {gallerySection}
  );
}

The above caused the error. 以上导致错误。 I fixed the problem by changing the return() section to: 我将return()部分更改为：

return (
  

    {gallerySection}
  
);

...or simply: ...或简单地说：

return gallerySection

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#6楼

You were just using the keys of object, instead of the whole object! 您只是在使用对象的键，而不是整个对象！

More details can be found here: https://github.com/gildata/RAIO/issues/48 可以在这里找到更多详细信息： https : //github.com/gildata/RAIO/issues/48

 import React, { Component } from 'react'; import PropTypes from 'prop-types'; class SCT extends Component { constructor(props, context) { super(props, context); this.state = { data: this.props.data, new_data: {} }; } componentDidMount() { let new_data = this.state.data; console.log(`new_data`, new_data); this.setState( { new_data: Object.assign({}, new_data) } ) } render() { return ( 
 this.state.data = {JSON.stringify(this.state.data)} 
 
 {this.state.new_data.name}
 {this.state.new_data.description}
 {this.state.new_data.dependtables}
 
 
 ); } } SCT.propTypes = { test: PropTypes.string, data: PropTypes.object.isRequired }; export {SCT}; export default SCT;