在我组件的渲染函数中,我有:

render() {
    const items = ['EN', 'IT', 'FR', 'GR', 'RU'].map((item) => {
      return (<li onClick={this.onItemClick.bind(this, item)} key={item}>{item}</li>);
    });
    return (
      <div>
        ...
                <ul>
                  {items}
                </ul>
         ...
      </div>
    );
  }

一切呈现良好,但当点击<li>元素时,我收到以下错误:

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}). 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. Check the render method of Welcome.

如果我改成this。onitemclick。绑定(this, item) to (e) => onItemClick(e, item)内的映射函数,一切都按预期工作。

如果有人能解释我做错了什么,为什么我会得到这个错误,那就太好了

更新1: onItemClick函数如下所示。setState会导致错误消失。

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

但是我不能删除这一行,因为我需要更新这个组件的状态


当前回答

在使用Firebase的情况下,如果把它放在import语句的末尾不能工作,那么你可以尝试把它放在一个生命周期方法中,也就是说,你可以把它放在componentWillMount()中。

componentWillMount() {
    const firebase = require('firebase');
    firebase.initializeApp({
        //Credentials
    });
}

其他回答

我的问题是忘记了道具周围的花括号被发送到一个表示组件:

之前:

const TypeAheadInput = (name, options, onChange, value, error) => {

const TypeAheadInput = ({name, options, onChange, value, error}) => {

当您尝试将对象呈现为子元素时,可能会发生这种情况,您可以通过查找下面的场景找到根本原因。

Check if you are using any double braces in JSX - <span>{{value}}</span> and change it to <span>{value}</span> (I did this mistake since I just moved from Angular to React). Check of return statements wrapped around braces like below and remove it. render() { let element = ( <span>text</span> ); return ( {element} // => Remove this extra brace ) } Check any other unintentional way you are using object in the JSX let nestedObjected = { a : '1', b : { c: '2' } }; {Object.keys(nestedObjected).map((key) => { return ( <div> <span>{nestedObjected[key]}</span> // This will cause issue since it will resolve to an object </div> ); })}

如果使用无状态组件,请遵循以下格式:

const Header = ({pageTitle}) => (
  <h1>{pageTitle}</h1>
);
export {Header};

这似乎对我很管用

正如我所经历的一样,除了添加“__html”来标记它之外,我通过将标记的HTML放入具有属性“dangerlysetinnerhtml”的span中来解决,如下所示:

  createMarkup(innerHtml){
    return {__html: innerHtml};
  }

  render = () => {
    return (
      <span dangerouslySetInnerHTML={
      this.createMarkup(this.props.details.entryContent)}/>
    );
  }

我也得到了这个“对象是无效的React子”错误,对我来说,原因是在我的JSX调用异步函数。见下文。

class App extends React.Component {
    showHello = async () => {
        const response = await someAPI.get("/api/endpoint");

        // Even with response ignored in JSX below, this JSX is not immediately returned, 
        // causing "Objects are not valid as a React child" error.
        return (<div>Hello!</div>);
    }

    render() {
        return (
            <div>
                {this.showHello()}
            </div>
        );
    }
}

我了解到React不支持异步渲染。React团队正在研究如下所示的解决方案。