PWA App Barcode Scanner Integration

Project Title:
Barcode Scanner with Auto Entry in PWA App

Description:
I have a live PWA app (easy-hisab.in/app)
built in HTML, CSS, and JavaScript
with Firebase backend.

I need a barcode scanning feature where
scanning a product barcode automatically
fills in the details — no manual typing needed.

Requirements:

1. SALES PAGE
Scan product barcode → product name and
price auto-fill → user selects quantity
→ sale entry saves automatically

2. STOCK PAGE
Scan product barcode → product details
auto-fill → stock quantity updates
automatically

3. INVOICE PAGE
Scan product barcode → product
automatically added to invoice items

Tech Stack Already in App:
- ZXing barcode library already integrated
- Firebase Firestore as database
- Products already stored in Firebase
- App is live at easy-hisab.in/app

Work Required:
- Connect ZXing scanner output to Firebase
- When barcode is scanned, search product
in Firebase and auto-fill all fields
- Must work on Android Chrome (mobile)
- No UI redesign needed

Deliverable:
- Single updated index.html file
- Must be tested on a real mobile device
before delivery

Budget: ₹1,500 - ₹2,500
Timeline: 3 to 5 days

Note: ZXing and Firebase are already
set up — only integration work is needed.
This should be a quick task for an
experienced developer.