CSV Viewer PWA

A lightweight, fast CSV file viewer with sorting, filtering, and statistics. Set it as your default .csv handler for instant data inspection.

Features

• 🚀 Instant loading - Offline-first PWA with service worker caching
• 📂 File handler - Set as default app for .csv, .tsv files (Chromium browsers)
• 🔍 Search/Filter - Full-text search across all columns
• ↕️ Sortable columns - Click headers to sort (numbers and text)
• 📊 Column statistics - Min, max, avg, median, sum, top values
• 💾 Export filtered - Save your filtered/sorted results
• 🎨 Dark/Light mode - Toggle between themes
• 🔄 Reset All - Clear search, sort, and filters in one click
• 📄 Pagination - Handle large files efficiently (configurable rows per page)
• 📱 Responsive - Works great on desktop and mobile

Quick Start

Option A: Use the hosted version

Visit the GitHub Pages deployment linked on this repo — no install needed.

Option B: Run locally

cd csv-viewer
python3 -m http.server 8000

Then visit: http://localhost:8000

2. Install as PWA

1. Open the app in Chrome/Edge/Brave
2. Look for the install icon in the address bar
3. Click to install

3. Set as default file handler

After installing:

1. Right-click any .csv file
2. Choose "Open with" → "Choose another app"
3. Select "CSV Viewer" from the list
4. Check "Always use this app"

Now every CSV file opens instantly with sorting and filtering!

Features in Detail

Sorting

Click any column header to sort. Click again to reverse direction. Works intelligently:

• Detects numbers and sorts numerically (handles comma-formatted numbers)
• Falls back to alphabetical for text
• Shows sort indicator (↑/↓)
• Sorting and search compose — filtering keeps your sort, sorting keeps your filter

Search/Filter

Type in the search box to filter rows. Searches across ALL columns. Great for finding specific values quickly.

Column Statistics

Click the 📊 button on any column header to see:

• Total/unique/empty values
• For numbers: sum, average, median, min, max
• Top 10 most common values with percentages

Export Filtered Data

After filtering/sorting, click "Export Filtered" to download a CSV with just the rows you're viewing.

Keyboard Shortcuts

• Ctrl/Cmd + O - Open file
• Ctrl/Cmd + F - Focus search
• Ctrl/Cmd + D - Toggle dark/light mode

Supported Formats

• .csv - Comma-separated values
• .tsv - Tab-separated values
• .txt - Generic delimited text (auto-detects delimiter)

Uses PapaParse for robust CSV parsing - handles quoted fields, embedded commas, and edge cases correctly.

Performance

Handles large files well:

• Pagination keeps UI fast (50/100/250/500 rows per page)
• Loading spinner for large file parsing
• Efficient filtering and sorting
• Tested with files up to several MB

Browser Support

• ✅ Chrome/Edge/Brave (full support including file handler)
• ✅ Firefox (works, but no file handler API yet)
• ✅ Safari (works, but no file handler API yet)

Development

Files:

• index.html - App shell
• app.js - Main logic (parsing, sorting, stats)
• styles.css - Table styling
• manifest.json - PWA configuration
• service-worker.js - Offline caching

Libraries Used

• PapaParse - CSV parsing
• Service Worker API - Offline support
• File Handling API - Default file handler

Why This Exists

Opening CSV files shouldn't require:

• Starting Excel (heavy, slow)
• Opening Google Sheets (requires upload, internet)
• Using a text editor (no structure)

This gives you instant, beautiful CSV inspection with sorting and stats. Double-click → done.

License

MIT - do whatever you want with it

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Built for instant CSV inspection without the bloat 📊