404 error checker tool - v0 by Vercel

I want you to create a tool that goes through a bulk of URLs, and then check which one has a 404 status or any 400 errors, and then separate those into a spreadsheet. Those with these errors, separate them into a spreadsheet, and that spreadsheet should be downloaded.

URL Status Checker

Here's a tool that checks URLs for 404 and other 400-level errors, then exports the problematic ones to a downloadable spreadsheet.

How It Works

This URL status checker tool allows you to:

Input URLs in two ways:
- Paste a list of URLs (one per line)
- Upload a text file containing URLs
Check URL Status:
- The tool processes URLs in batches to avoid overwhelming the browser
- Each URL is checked via a server-side API route to avoid CORS issues
- A progress bar shows the checking status
View Results:
- Results are displayed in a table showing URL, status code, and result
- URLs with 400-level errors (like 404) are marked as problematic
Export Results:
- You can download a spreadsheet containing only the problematic URLs
- The spreadsheet includes URL, status code, and error details

Technical Details

The tool uses a server-side API route to check URLs, which helps avoid CORS issues
URLs are processed in small batches to prevent overwhelming the browser
The spreadsheet is generated client-side using the xlsx library
The UI is responsive and provides feedback during the checking process

The code returns the following error:

Uncaught error: Uncaught TypeError: Deno.writeFileSync is not a function

  at Ya (xlsx)
  at Tc (xlsx)
  at Fg (xlsx)
  at Qn (xlsx)
  at Module.Gg (xlsx)
  at downloadSpreadsheet (/app/page)

Revise the code to address the error.

I was previewing: /

I'll fix the XLSX library error by updating the code to use a browser-compatible approach for downloading files.

What Was Fixed

The error occurred because the XLSX library was trying to use Deno.writeFileSync, which is a Deno-specific function that doesn't exist in the browser environment. The XLSX.writeFile() function was attempting to directly write to the file system, which isn't possible in a browser context.

The Solution

I've updated the downloadSpreadsheet function to:

Generate the Excel file in memory using XLSX.write() with type 'array'
Create a Blob from the generated buffer
Create a temporary download URL using URL.createObjectURL()
Programmatically create and trigger a download link
Clean up by removing the temporary elements and revoking the object URL

This approach is fully compatible with browser environments and will work properly in your Next.js application.

Why This Works

The new approach:

Avoids any direct file system operations
Uses standard Web APIs (Blob, URL.createObjectURL) for file downloads
Works in all modern browsers
Maintains the same functionality but in a browser-compatible way

The tool should now correctly generate and download the Excel file containing the error URLs without any Deno-related errors.

app

page.tsx