Скачать или смотреть Resolving SyntaxError: Unexpected token ' ' in Node.js and React Applications

Discover how to fix the error `SyntaxError: Unexpected token ' '` when making API calls in your Node.js and React application with this comprehensive guide.
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This video is based on the question https://stackoverflow.com/q/74552750/ asked by the user 'Matan Fadida' ( https://stackoverflow.com/u/13622774/ ) and on the answer https://stackoverflow.com/a/74555165/ provided by the user 'ahmadsandid' ( https://stackoverflow.com/u/17980409/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding and Fixing the SyntaxError: Unexpected token '<' Error in Node.js and React

When working with a Node.js backend and a React frontend, it can be frustrating to encounter errors that disrupt the flow of your application. One such error is the notorious SyntaxError: Unexpected token '<'. This error usually arises when you're trying to parse a JSON response but get an unexpected HTML document instead.

The Problem

In your specific case, you're fetching data from your backend using the fetch API but receiving an HTML response instead of JSON. The error message indicates that the response begins with <!DOCTYPE ..., which is a clear sign that an HTML document is being returned.

Why This Happens

Here’s the context:

The fetch request is made to the base URL ('/'), which, if not routed properly, returns the main HTML file (the index.html used by React).

Since there is no API endpoint responding to the root URL, the server is defaulting to serve the HTML file.

Solution

To resolve this error, you'll need to ensure that your fetch requests are directed to the correct API endpoints. Below are detailed steps to correct your setup.

Step 1: Update Your Routing

It’s recommended to prefix your API routes. This approach helps differentiate between static files served by React and your API endpoints. We’ll create a new router to handle the /api prefix.

Create an api.route.js File

Inside your /routes folder, create a new file called api.route.js:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Update Your Index File

Now, modify your main server file to use the API router. Here’s how it looks:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Adjust Your Fetch Request

In your React component, update the fetch call to point to the new API route:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these steps, you’ll effectively route your API requests to the correct endpoints and eliminate the SyntaxError: Unexpected token '<'. Remember to always verify URLs and keep your routes organized. With a clear separation of concerns, you'll find it much easier to manage your Node.js and React applications. Happy coding!