Next.js Error: Found Page Without a React Component as Default Export – How to Fix

Understanding the Error

Next.js is a popular framework built on top of React that allows for server-side rendering, static site generation, and more. A common error developers encounter while working with Next.js is the error message which reads “Found page without a React Component as default export“. This essentially warns you that Next.js expects every page in the pages directory to export a React component by default, but the mentioned file violates this rule.

When you create a file in the ‘pages’ folder, Next.js treats it as a page on your website. Each page file must export a default React component because Next.js uses that component to render the page’s content. If Next.js checks a file in the pages directory and does not find a default React component export, it throws this error, indicating a problem with the export statement or the lack of a React component within that file.

Correcting the Export Statement

Let’s resolve the error by ensuring that we have a React component that is exported as the default export of the file. We’ll examine our file contained in the pages directory and identify the React component. Once identified, we’ll add the export default keyword before the component definition.

For example, if you have a page component defined like this:

class HomePage extends React.Component { 
   render() { 
      return <div>Welcome to my homepage!</div>; 
   } 
} 

You should correct the export by adding the default keyword:

export default class HomePage extends React.Component { 
   render() { 
       return <div>Welcome to my homepage!</div>; 
   } 
}

Exporting a Functional Component

If you’re using functional components in your project, the idea remains the same. The functional component should be exported as default. Suppose your component looks something like this:

function HomePage() { 
   return <div>Welcome to my homepage!</div>; 
}

The corrected version with a default export will be:

export default function HomePage() { 
    return <div>Welcome to my homepage!</div>; 
} 

Using Export Default with Arrow Functions

Many developers prefer using arrow functions for functional components. If this matches your coding style, ensure your arrow function is also exported as default, like so:

const HomePage = () => <div>Welcome to my Sling Academy!</div>; 
export default HomePage; 

Alternatively, you can export it directly in the declaration:

export default () => <div>Welcome to Sling Academy!</div>; 

Troubleshooting Other Potential Issues

Sometimes, the issue may not be with exporting a component but with how the component is defined. Ensure that your file is actually defining a valid React component. The component should return JSX or call React.createElement, and it should not return undefined or null without rendering a React element. Additionally, check for typos in your component or file names, as imports might fail due to a name mismatch, resulting in the same error.

Complete Code Example

As an example, here’s a complete functional component file for a Next.js project that gets rid of the error:

// pages/index.js 
import React from 'react'; 
function HomePage() { 
    return ( 
       <div> 
          <h1>Welcome Sling Academy!</h1> 
       </div> 
    ); 
} 
export default HomePage;

Ensure that the file is placed within the pages directory and has a unique name. The default export will act as the entry point for the corresponding route, making the error disappear and your Next.js app function as intended.