The Fine-Grained Reactivity of State Management

It knows which component it's in even though you don't pass the component to it. There is a stack because the component has to be called and it pushes the component into the state management so that it knows. You're not re executing your if you have a component app and that thing opts into a signal reads a signal, the component is not re executed just the getter is,. It returns a new value in place, hence fine-grained reactivity.