nestedSignal utility

[DDtMM]

nestedSignal utility

[DDtMM]

Here was a first attempt at the code, but it didn't really make sense.

Issue 1: A variable is needed that gets the current context the signal is in. This is probably getActiveConsumer(). I don't know if this is available in Angular 16.
Issue 2: how are multiple calls distinguished? An anonymous function would be the best, but it would be hard to distinguish from a signal, and what if somebody tries to reuse the same one more than once for some reason?

export function nestedSignal<V extends (...args: never[]) => Signal<unknown>>(fn: V, ...params: Parameters<V>): () => ReturnType<V> {
  let isReady = false;
  let source: ReturnType<V>;
  return () => {
    if (isReady) {
      return source;
    }
    source = fn.apply(fn, params) as ReturnType<V>;
    isReady = true;
    return source;
  };
}