Add linkedSignalState

[Harpush]

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

signals

Information

Currently signal state is a strong utility to handle state even outside signal store.
The missing part is allowing that state to be a linked signal.

I propose a new linkedSignalState which will allow deriving the state based on another signal.

This will allow resetting the state on signal change - or any other state transformation based on some other signal change.

Describe any alternatives/workarounds you're currently using

Currently either don't use signal state or use an effect to update the state.

I would be willing to submit a PR to fix this issue

• Yes
• No

[Harpush]

An example:

const a = signal(2);

// The state is based on another signal (linked)
const state = linkedSignalState(() => ({value: a() + 1}));
// or
const state = linkedSignalState({
    source: a,
    computation: (source) => ({value: source + 1})
});

patchState(state, {value: 5}); // Patch state like any other state
console.log(state.value()); // Deep signal

[rainerhahnekamp]

Thank you, @Harpush. Rest assured, we are fully aware of the need for this and are actively discussing various strategies to address it. There are also multiple scenarios where linkedSignal could come into play, and we’re taking those into consideration.

We’re not rushing this—our goal is to ensure we get it right the first time. 😊