The component relies on zxing-typescript which currently supports some 2D and 1D barcode formats, but not them all.
On iOS-Devices with iOS < 14.3 camera access works only in native Safari and not in other Browsers (Chrome,...) or Apps that use an UIWebView or WKWebView. This is not a restriction of this component but of the limited WebRTC support by Apple. The behavior might change in iOS 11.3 (Apr 2018?, not tested) as stated here
iOS 14.3 (released in december 2020) now supports WebRTC in 3rd party browsers as well 🎉