Barcode Reader & Scanner

The Barcode Reader decodes 1D linear barcodes through a three-stage fallback pipeline rather than a single library. It first tries the browser's native BarcodeDetector API (available in Chrome) configured for nine symbologies: ean_13, ean_8, upc_a, upc_e, code_128, code_39, code_93, codabar, and itf (Interleaved 2 of 5). If the native API is unavailable or finds nothing, it loads html5-qrcode via scanFileV2, which has stronger Code-128 handling. As a final fallback it loads @ericblade/quagga2 and re-attempts the decode three times with progressively different locator patch sizes (medium, then large, then small, each with halfSample disabled and locate enabled, inputStream size 800), since the right patch size depends on how large the barcode appears in the frame. Quagga is run with nine readers (ean_reader, ean_8_reader, upc_reader, upc_e_reader, code_128_reader, code_39_reader, code_93_reader, codabar_reader, i2of5_reader). When all three stages fail it reports 'No barcode found in the image' and suggests a clearer image or different angle.

Beyond raw decoding, the tool classifies what it scanned and links out for lookup. An EAN-13 value beginning with 978 or 979 is recognized as a book and labeled 'Book (ISBN-13)', a UPC-A code (or an EAN-13 starting with 0) is labeled as a retail product, and other EAN-13/EAN-8 values are tagged as international products; each result gets a 'Search Product' button that opens a Google query (e.g. 'ISBN 978...', 'UPC ...', 'EAN ...'). The decoded value is also re-rendered as a clean barcode image using JsBarcode (width 2, height 80, value displayed), mapping the scanned format back to JsBarcode's EAN13/EAN8/UPC/UPCE/CODE128/CODE39/CODE93/codabar/ITF formats, with a CODE128 fallback for any value the strict format rejects. Every scan is appended to a 'Recent Scans' history capped at the last 20 entries, each copyable to clipboard.

A camera mode is included for live scanning: it requests getUserMedia with facingMode 'environment' (rear camera) at an ideal 1280x720, draws each video frame to a canvas in a requestAnimationFrame loop, and runs the same detection on the frame (BarcodeDetector first, Quagga2 as fallback), stopping the stream on the first successful read. A SwitchCamera control toggles between the rear ('environment') and front ('user') cameras. All scanning happens locally in the browser via these client-side libraries and the canvas/Image APIs; images and camera frames are processed in-page and not uploaded. Because these are 1D linear symbologies with no error correction, the in-app error tip notes that the barcode should be clearly visible, straight, and undamaged for a reliable read.