[Enhancement] Add support for UPC-A on iOS

[thomasgalliker]

Summary

When EAN_13 barcode format is enabled, it still scans UPC_A barcodes and just adds a zero to the beginning of them. In fact, this isn't surprising given that EAN_13 is a superset of UPC_A, and 12-digit UPC_A codes can be converted to an equivalent EAN_13 code by prepending a zero to the code.

tbd: How can we implement UPC_A barcode scanning without just padding the leading '0' and returning an EAN_13?

Links

• https://developer.apple.com/documentation/avfoundation/avmetadataobjecttypeean13code?language=objc
• https://developer.apple.com/library/archive/technotes/tn2325/_index.html#//apple_ref/doc/uid/DTS40013824-CH1-IS_UPC_A_SUPPORTED
• https://stackoverflow.com/questions/22767584/ios7-barcode-scanner-api-adds-a-zero-to-upca-barcode-format
• UPC_A support on iOS? EddyVerbruggen/nativescript-barcodescanner#176