fix: exclude class instance from DeepSignal

[rainerhahnekamp]

This is a draft. Whoever has an idea, for the fix, please let me know. It tries to solve the following problem.

class User {
  id = 0;
  name = 'Konrad';
}

const state = signalState({ user: new User() });
const user = state.user; // should not be DeepSignal<User>

IsRecord tries to differentiate a class instance from object literal by checking
if a prototype is there or not.

Fore more details, checkout the commit.

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PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Closes #4604

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[ ] No

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[jdegand]

I assume you used constructor: Function and that didn't work.

Maybe, check if the constructor.name is 'Object' (true for object literals but not for class instances)?

export type IsRecord<T> = T extends object
  ? T extends unknown[]
    ? false
    : T extends Set<unknown>
    ? false
    : T extends Map<unknown, unknown>
    ? false
    : T extends Function
    ? false
    : T extends { prototype: unknown } // Checks for class instances
    ? false
    : T extends { constructor: { name: string } }
    ? T['constructor']['name'] extends 'Object'
      ? true
      : false
    : false
  : false;

[rainerhahnekamp]

@jdegand: Nope, in the meantime, I've pulled out a TypeScript Playground, which allows us to experiment a little bit.

I am going to share the Link in the original issue, and I'm going to close this PR since it is not ready yet.