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You must bear in mind that in order to read a barcode you need specific hardware, you can start with a writing code that works by a kind of commands that it injects, as it were, into the operating system.
Connected with USB to the client
You must have it configured according to the type of reader (be 2D for PDF417 code or similar codes)
Bring the code closer to the reader
If you have an entry field in which the cursor is on the or in an excel you will see that the reading is transferred to the document.
Web or Mobile
The answer is depends, you can do it in both ways, everything varies according to the specific need you have.
As you have web knowledge, it will be very easy to implement a hybrid application with Ionic, since you know Angular, so your learning curve will be much shorter, also, currently in version 4 (Beta) Angular is your most stable customer.
Personally I think that, the more solutions we can provide to a client, we will be much more efficient. But, to perform this functionality we must not use a reader, we must develop an application that can read code through its camera, a clear example can be found in the official documentation of ionic
A fast, energy-efficient and highly configurable QR code scanner for Cordova applications.
Requires Cordova plugin:
For more information, see the QR Scanner Add-on documents: qr code repository