region-signal about region-core

[dancerphil]

Close since we can not implement useValue(key) in MappedRegion. (If can, why not a hook?)

The deep reason is that it must not exist a pattern which is isomorphic to function: key => value to represent value ^ key.(And also unnecessary.)

[dancerphil]

Maybe we can introduce a new api called signalMap to fix this:

const signalMap = createSignalMap(() => createSignal(0));
const signal = signalMap(key);

const loadUser = signal.loadBy(asyncFuncion);

// call loadUser in application lifecycle
loadUser({userId: 1});

const Component = () => {
    const value = signal.value;
    const loading = signal.loading;
    const error = signal.error;

    // ...
    return <div>{value}</div>;
}