Files
element-call-Github/src/useBehavior.ts
Robin b3863748dc Replace many usages of useObservableEagerState with useBehavior
This hook is simpler in its implementation (therefore hopefully more correct & performant) and enforces a type-level distinction between raw Observables and Behaviors.
2025-07-11 00:24:46 -04:00

26 lines
712 B
TypeScript

/*
Copyright 2025 New Vector Ltd.
SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
Please see LICENSE in the repository root for full details.
*/
import { useCallback, useSyncExternalStore } from "react";
import { type Behavior } from "./state/Behavior";
/**
* React hook which reactively reads the value of a behavior.
*/
export function useBehavior<T>(behavior: Behavior<T>): T {
const subscribe = useCallback(
(onChange: () => void) => {
const s = behavior.subscribe(onChange);
return (): void => s.unsubscribe();
},
[behavior],
);
const getValue = useCallback(() => behavior.value, [behavior]);
return useSyncExternalStore(subscribe, getValue);
}