Understanding the Context

The provided code snippet aims to create a website feature that allows users to download files. It uses JavaScript and the Fetch API to retrieve the file data and initiate the download process. However, the developer is encountering two types of errors, which seem to be related to larger file sizes.

Error 1: Failed to Fetch

The first error, "Uncaught (in promise) TypeError: Failed to fetch," suggests an issue with the fetch request itself. This error can occur for various reasons, such as:

• Network connectivity issues
• CORS (Cross-Origin Resource Sharing) restrictions
• Incorrect URL or file path

Error Handling for Failed Fetch Request

To handle this error, proper error checking and handling should be implemented within the fetch promise chain. The provided solution incorporates a catch block to log any errors that occur during the fetch request.

Error 2: net::ERR_FAILED

The second error, "downloader.js:7 GET https://pathToFile net::ERR_FAILED 200," indicates that the fetch request was successful (HTTP 200 response), but an error occurred during the response processing. This error is often associated with larger file sizes or specific file types.

Error Handling for Response Processing

To handle this error, additional checks should be implemented within the fetch promise chain to ensure that the response is valid and can be processed correctly. The provided solution checks the response.ok property before attempting to process the response as a Blob.

JSON Fetch for File Metadata

The code snippet also includes a separate fetch request to retrieve a JSON file containing metadata about the file to be downloaded, such as the version number and file extension. This information is used to construct the filename for the download.

Improved Error Handling and Code Organization

The suggested solution incorporates the following improvements:

• Proper error handling for both fetch requests (file data and JSON metadata)
• Checking the response.ok property before processing the response as a Blob
• Consolidating the fetch request for file data into a single function (FetchTheRest)
• Removing the async/await syntax, as it is not necessary for this use case

Conclusion

By implementing proper error handling techniques and following best practices for code organization, the provided solution aims to address the issues encountered when downloading files, especially larger ones, using JavaScript and the Fetch API. It also highlights the importance of handling various types of errors that can occur during web development, particularly when working with asynchronous operations and file-related tasks.