Revert useComputed changes in react (#796)

* Revert "Reflect logic from  #754 in react (#757)"

This reverts commit 18f1aa1.

* Add changeset

Author: JoviDeCroock

.changeset/friendly-zebras-provide.md

@@ -0,0 +1,5 @@
+---
+"@preact/signals-react": minor
+---
+
+Revert the changes to `useComputed`, sincere apologies for the inconvenience we've discussed this at length and are going to side on the perf side.

packages/react/runtime/src/index.ts

@@ -399,13 +399,9 @@ export function useComputed<T>(
 	compute: () => T,
 	options?: SignalOptions<T>
 ): ReadonlySignal<T> {
-	const [$fn, $computed] = useMemo(() => {
-		const $fn = signal(compute);
-		return [$fn, computed(() => $fn.value(), options)] as const;
-	}, []);
-
-	$fn.value = compute;
-	return $computed;
+	const $compute = useRef(compute);
+	$compute.current = compute;
+	return useMemo(() => computed<T>(() => $compute.current(), options), Empty);
 }
 
 export function useSignalEffect(

packages/react/test/shared/updates.tsx

@@ -18,7 +18,6 @@ import {
 	useContext,
 	createContext,
 	useRef,
-	useCallback,
 } from "react";
 import type { FunctionComponent } from "react";
 import { renderToStaticMarkup } from "react-dom/server";
@@ -849,59 +848,4 @@ export function updateSignalsTests(usingTransform = false) {
 			expect(cleanup).to.have.been.calledWith("foo", isReact16 ? child : null);
 		});
 	});
-
-	describe("useComputed", () => {
-		it("should recompute and update dependency list when the compute function changes", async () => {
-			const s1 = signal(1);
-			const s2 = signal("a");
-
-			function App({ x }: { x: Signal }) {
-				const fn = useCallback(() => {
-					return x.value;
-				}, [x]);
-
-				const c = useComputed(fn);
-				return <span>{c.value}</span>;
-			}
-
-			await render(<App x={s1} />);
-			expect(scratch.textContent).to.equal("1");
-
-			await render(<App x={s2} />);
-			expect(scratch.textContent).to.equal("a");
-
-			await act(() => {
-				s1.value = 2;
-			});
-			expect(scratch.textContent).to.equal("a");
-
-			await act(() => {
-				s2.value = "b";
-			});
-			expect(scratch.textContent).to.equal("b");
-		});
-
-		it("should not recompute when the compute function doesn't change and dependency values don't change", async () => {
-			const s1 = signal(1);
-			const spy = sinon.spy();
-
-			function App({ x }: { x: Signal }) {
-				const fn = useCallback(() => {
-					spy();
-					return x.value;
-				}, [x]);
-
-				const c = useComputed(fn);
-				return <span>{c.value}</span>;
-			}
-
-			await render(<App x={s1} />);
-			expect(scratch.textContent).to.equal("1");
-			expect(spy).to.have.been.calledOnce;
-
-			await render(<App x={s1} />);
-			expect(scratch.textContent).to.equal("1");
-			expect(spy).to.have.been.calledOnce;
-		});
-	});
 }