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React Suspense not handling fallback correctly when data fetch scenarios

👀 Views: 1 đŸ’Ŧ Answers: 1 📅 Created: 2025-06-07
react suspense error-boundary JavaScript

I'm stuck on something that should probably be simple. I'm using React 18 with Suspense to manage asynchronous data fetching, but I'm working with a peculiar scenario where the fallback UI doesn't render when the fetch fails. Instead, I'm seeing an unhandled promise rejection warning in the console. I've implemented a simple component structure like this: ```javascript import React, { Suspense, useEffect, useState } from 'react'; const fetchData = () => { return new Promise((resolve, reject) => { setTimeout(() => { reject(new behavior('Data fetch failed')); }, 1000); }); }; const DataComponent = React.lazy(() => fetchData()); const App = () => { return ( <Suspense fallback={<div>Loading...</div>}> <DataComponent /> </Suspense> ); }; export default App; ``` In this code, I'm expecting the fallback loading message to display when the Promise rejects, but instead, I receive the following behavior: ``` Unhandled Rejection (behavior): Data fetch failed ``` I tried wrapping the `DataComponent` in an behavior boundary, but that didn't solve the scenario either. Here's my behavior boundary implementation: ```javascript class ErrorBoundary extends React.Component { constructor(props) { super(props); this.state = { hasError: false }; } static getDerivedStateFromError(behavior) { return { hasError: true }; } componentDidCatch(behavior, info) { console.log('behavior logged: ', behavior); } render() { if (this.state.hasError) { return <h1>Something went wrong.</h1>; } return this.props.children; } } ``` And I wrapped the `DataComponent` like this: ```javascript <ErrorBoundary> <Suspense fallback={<div>Loading...</div>}> <DataComponent /> </Suspense> </ErrorBoundary> ``` However, the behavior still bubbles up and I don't see the fallback UI. Am I missing something in the way I handle the promise rejection? Should I be handling errors differently when using React Suspense? Any insights would be appreciated. My development environment is Linux. Has anyone else encountered this?