使用 React 18 和 suspense，如何显示特定的错误，而不仅仅是在 ErrorBoundary 中回退

Question

我有一个这样结构的组件，我的 ErrorBoundary 包装了我的 Suspense 元素。

function App() {
  return (
    <ErrorBoundary fallback={<h2>Could not fetch cities.</h2>}>
      <Suspense fallback={<div>Loading..</div>}>
        <MyList />
      </Suspense>
    </ErrorBoundary>
  );
}

MyList 组件包含一个 SWR 数据获取挂钩，如下所示：

const { data } = useSwr(`/api/mydata`, fetcher, {
      suspense: true,
    });

我的 fetcher 方法抛出如下错误：

  const rsp = await fetch(url);
  if (rsp.ok) {
    return await rsp.json();
  } else {
    const MyError = function (message, status) {
      this.message = `${message} from url ${url} status code:${status}`;
      this.status = status;
    };
    throw new MyError(rsp.statusText, rsp.status);
  }
}

当错误发生时，我不知道如何让我的 UI 显示抛出的值（即 MyError class 中的内容）

Answer 1

我不确定是否有一些库与名为 ErrorBoundary 的组件一起使用，但您可以编写自己的库来执行此操作，如下所示：

class MyErrorBoundary extends React.Component {
  state = { error: null }

  static getDerivedStateFromError(error) {
    return { error };
  }

  render() {
    if (this.state.error) {
      // render whatever you like for the error case
      return <h2>{this.state.error.message}</h2>
    } else {
      return this.props.children
    }
  }
}

Answer 2

按照docs, you have access to error and errorInfo in componentDidCatch. You can set it to state of the ErrorBoundary. What you can do is use a third-party library (react-json-tree)查看错误就好了

import JSONTree from 'react-json-tree';

class ErrorBoundary extends React.Component {
  constructor(props) {
    super(props);
    this.state = { hasError: false, error: null, errorInfo: null };
  }

  static getDerivedStateFromError(error) {
    // Update state so the next render will show the fallback UI.
    return { hasError: true };
  }

  componentDidCatch(error, errorInfo) {
    // You can also log the error to an error reporting service
    this.setState({ error, errorInfo });
  }

  render() {
    if (this.state.hasError) {
      // You can render any custom fallback UI
      return <JSONTree data={this.state.error}/>;
    }

    return this.props.children; 
  }
}

Answer 3

您应该在 ErrorBoundary 组件中使用此生命周期：

https://reactjs.org/docs/react-component.html#componentdidcatch

类似（改编自文档，解释如何以被ErrorBoundary拦截的方式触发错误：

// In ErrorBoundary

componentDidCatch(error, errorInfo) {
  this.setState({
    error: error,
    errorInfo: errorInfo
  });
}

// In MyList

buggyMethod() {
  fetch("something-wrong").then(error => this.setState({ error }));
}

render() {
 if(this.state.error){
   throw this.state.error;
 }
 return <span>Something cool!</span>;
}

备注

似乎有点连线，但与官方文档“现场演示”部分中使用的技术相同：

https://reactjs.org/docs/error-boundaries.html#live-demo

Answer 4

这是我要找的答案：

fetcher.js

export async function fetcher(url) {
  const rsp = await fetch(url);
  if (rsp.ok) {
    return await rsp.json();
  } else {
    const MyError = function (message, status) {
      this.message = `${message} from url ${url} status code:${status}`;
      this.status = status;
    };
    throw new MyError(rsp.statusText, rsp.status);
  }
}

ErrorBoundary.js

class ErrorBoundary extends React.Component {
  constructor(props) {
    super(props);
    this.state = { hasError: false };
  }

  static getDerivedStateFromError(error) {
    // Update state so the next render will show the fallback UI.
    return { hasError: true, message: error?.message, status: error?.status };
  }

  render() {
    function addExtraProps(Component, extraProps) {
      return <Component.type {...Component.props} {...extraProps} />;
    }

    if (this.state.hasError) {
      return addExtraProps(this.props.fallback, {
        errorMessage: this.state.message,
        errorStatus: this.state.status,
      });
    }
    return this.props.children;
  }
}

然后用法是这样的：

function CityLayout(props) {
  const { setSelectedCityId } = useContext(CityContext);
  return (
    <>
      <CityListMaxDDL />
      <CityList displayCount={5} />
      <CityDetail cityId={setSelectedCityId} />
    </>
  );
}

function App() {
  function MyErrorBoundaryFallback({ errorMessage, errorStatus }) {
    return (
      <div className="container">
        <h1>Error</h1>
        <div className="row">
          Error Status: <b>{errorStatus}</b>
        </div>
        <div className="row">
          ErrorMessage: <b>{errorMessage}</b>
        </div>
      </div>
    );
  }

  return (
    <ErrorBoundary fallback={<MyErrorBoundaryFallback />}>
      <Suspense fallback={<div>Loading..</div>}>
        <div className="container">
          <CityProvider>
            <CityLayout />
          </CityProvider>
        </div>
      </Suspense>
    </ErrorBoundary>
  );

使用 React 18 和 suspense，如何显示特定的错误，而不仅仅是在 ErrorBoundary 中回退

With React 18 and suspense, how to display specific errors, not just fallback in ErrorBoundary

reactjs

react-suspense

swr