Why Does My React Fetch Request Fail with \'Unexpected End of Input\' in No-CORS Mode?

Handling Response: Unexpected End of Input with 'No-Cors' Mode

When trying to fetch data from a REST API using ReactJS, an unexpected end of input error may be encountered when parsing the response. This error typically occurs at the following line:

return response.json();

Root Cause: 'No-Cors' Mode

The error originates from using the 'no-cors' mode in the fetch request. When this mode is enabled, the response is considered opaque, meaning that frontend JavaScript cannot access the response body or headers.

Explanation of No-CORS

The purpose of setting the 'no-cors' mode is to prevent frontend JavaScript code from accessing responses that do not explicitly set Access-Control-Allow-Origin headers. This measure is intended to protect against cross-site scripting (XSS) attacks.

Solution: Removing 'No-Cors' Mode

To resolve the error, remove the 'no-cors' setting from the request. This will allow your code to access the response body and successfully parse the JSON response.

Additional Considerations

If you are encountering this error without using the 'no-cors' mode, consider the following steps:

• Ensure that the server is configured to send Access-Control-Allow-Origin headers in its response.
• If the request triggers a CORS preflight, consider using a CORS proxy to handle the preflight and relay the response.

The above is the detailed content of Why Does My React Fetch Request Fail with \'Unexpected End of Input\' in No-CORS Mode?. For more information, please follow other related articles on the PHP Chinese website!