Which @angular/* package(s) are relevant/related to the feature request?

core

Description

There is a difference in the design of the input() and of the signal() functions.

signal<T>() expects an argument and returns a Signal<T>, whereas input<T>() can be called with or without argument and returns a Signal<T | undefined> if no argument is passed.

Moreover, if we have code that uses input() without argument:

collapsed = input<boolean>();

and want to pass it options, then suddenly we're forced to

• pass an initial value, although the initial value is the same as before;
• change the generic type passed to the function, even though the type of the signal to create is the same as before:

collapsed = input<boolean | undefined>(undefined, { alias: 'appCollapsed' });

Proposed solution

Even though it requires a bit more code, I find the the result would be more consistent, more explicit, and less surprising if input() always required an initial value:

collapsed = input<boolean | undefined>(undefined);

• adding options requires just that: adding options
• the generic type is the same as the generic type of the created Signal
• it works the same way as signal()

Alternatives considered

NA