RxJS fromevent doesn't seems to work with keyup event

Question

I try to set a handler using fromEvent from RxJS library. I would like to Observe and Subscribe on a "keyup" event on an input field. So i make a function (typescript static method) to handle :

import { fromEvent, map, Subscription } from "rxjs";
import { AbstractControl } from "./../../forms/abstract-control";

export class InputHandler {
    public static getKeyupHandler(control: AbstractControl): Subscription {
        return fromEvent((control.supportFormField) as HTMLInputElement, 'keyup')
            .pipe(
                map((event: KeyboardEvent) => {
                    console.log(`${control.supportFormField.getAttribute('name')} has changed`)
                    control.value = (control.supportFormField as HTMLInputElement).value
                    if (control.value.trim().length === 0) {
                        control.value = ''
                    }
                    return control.value
                })
            )
            .subscribe((value: string) => {
                console.log(`Value for ${control.controlName} : ${control.value}`)
            })

    }
}

Expect to have some console, but got nothing at all nor in map neither in subscribe...

Controls are present in the DOM :

<input type="text" name="lastname" required data-rel="lastname">

Don't understand the reason why anything is produced by the fromEvent function.

If any idea...

Regards