Chrome extension: how to use serial port (now that apps are sunsetting)?

Question

Aim: I am attempting to write a little "thing" that can talk from my browser to the COM port of an Arduino.

Issue: My first attempt is to write an extension. Therefore I am requesting permission for serial in my manifest file. When loading the unpackaged extension via developer mode I receive the following error: 'serial' is only allowed for packaged apps, but this is a extension.

I see here that packaged app is an outdated term and I guess they just mean Chrome app. Now unfortunately it seems that Chrome is also discontinuing these Chrome apps as discussed here.

Question: So how should I access the serial functionality of Chrome apps/extensions/whatever new name you come up with?

Answer 1

"Web Serial API", navigator.serial, may be the best way looking forward. It has been available behind the #enable-experimental-web-platform-features flag in chrome://flags since chrome 77. It is due to go to Origin trials 80-82 then ship in 83.

Web Serial API allows serial interface directly from a progressive web app. There is a good tutorial at https://codelabs.developers.google.com/codelabs/web-serial/#0

You should probably avoid the older chrome.serial, available only in chrome apps, because from June 2020 Chrome Apps on Windows, Mac, and Linux will no longer be supported.