How to wrap an object contains a metric unit e.g. length= 10 m with Angular signals?

What is the correct implementation for an object in the signal world of angular?

A): all wrapped with signal as:
length=signal ({
nominalValue: signal(0),
unit: signal ("mm") })

or B): only the key: value wrapped with signals as:
length= {
nominalValue: signal(0),
unit: signal ("mm") }

or C) only the object itself wrapped with signal as:
length=signal( {
nominalValue: 0,
unit: "mm" })

By the html field and , I have to manipulate the objects key: values.
The following example is without signals:

<input [(ngModel)]='length.nominalValue'
(keyup)=' keyup (length)'>


Note: the triggered keyup() function will handle the changes by ...spread the object and at least invoke the related post calculations.

<button (click)='unitSwitch(length)'>
{{ length.unit }}</button>


The same for the units, but manipulated by a button.

Continue reading...