Note
Consider using the barcode-detector polyfill.
This project presently uses html5-qrcode which, in turn, uses the BarcodeDetector API. This API is not yet supported on all platforms, and html5-qrcode relies on zxing / zxing-js in those cases. On some platforms, such as iOS/Safari, this code can result in a serious performance regression especially when trying to scan large QR Codes, highlighting the importance of loading a newer and more performant BarcodeDetector API polyfill to support these platforms.
One such polyfill is barcode-detector, which is based on the very performant zxing-wasm / zxing-cpp. Loading the barcode-detector polyfill before html5-qrcode is loaded can offer considerable performance improvements and is therefore presently recommended whenever using this project where platforms may not have BarcodeDetector API support.
It is also important to note that, as of early 2025, html5-qrcode is not maintained and neither is the older zxing / zxing-js code. Once this project replaces its use of html5-qrcode, this message will be updated with new recommendations for enabling scanning on platforms that do not provide Web-native barcode scanning.