fix: Computed values that return the unchanged value of a tracked sig…

…nal are now recomputed when the source signal changes.

src/lwc/signals/__tests__/computed.test.ts

@@ -1,4 +1,4 @@
-import { $computed, $signal } from "../core";
+import { $computed, $effect, $signal } from "../core";
 
 describe("computed values", () => {
   test("can be created from a source signal", () => {
@@ -46,4 +46,15 @@ describe("computed values", () => {
     expect(computed.value).toBe(2);
     expect(anotherComputed.value).toBe(4);
   });
+
+  test("computed objects that return the same value as a tracked signal recomputes", () => {
+    const signal = $signal({ a: 0, b: 0 }, { track: true });
+    const computed = $computed(() => signal.value);
+    const spy = jest.fn(() => computed.value);
+    $effect(spy);
+    spy.mockReset();
+
+    signal.value.a = 1;
+    expect(spy).toHaveBeenCalled();
+  });
 });

src/lwc/signals/core.ts

@@ -53,7 +53,7 @@ function $effect(fn: VoidFunction): void {
   const effectNode: EffectNode = {
     error: null,
     state: UNSET
-  }
+  };
 
   const execute = () => {
     if (effectNode.state === COMPUTING) {
@@ -107,7 +107,7 @@ function computedGetter<T>(node: ComputedNode<T>) {
  */
 function $computed<T>(fn: ComputedFunction<T>): ReadOnlySignal<T> {
   const computedNode: ComputedNode<T> = {
-    signal: $signal<T | undefined>(undefined),
+    signal: $signal<T | undefined>(undefined, { track: true }),
     error: null,
     state: UNSET
   };
@@ -143,6 +143,8 @@ interface TrackableState<T> {
   get(): T;
 
   set(value: T): void;
+
+  forceUpdate(): boolean;
 }
 
 class UntrackedState<T> implements TrackableState<T> {
@@ -159,6 +161,10 @@ class UntrackedState<T> implements TrackableState<T> {
   set(value: T) {
     this._value = value;
   }
+
+  forceUpdate() {
+    return false;
+  }
 }
 
 class TrackedState<T> implements TrackableState<T> {
@@ -181,6 +187,10 @@ class TrackedState<T> implements TrackableState<T> {
   set(value: T) {
     this._value = this._membrane.getProxy(value);
   }
+
+  forceUpdate(): boolean {
+    return true;
+  }
 }
 
 /**
@@ -232,7 +242,10 @@ function $signal<T>(
   }
 
   function setter(newValue: T) {
-    if (isEqual(newValue, _storageOption.get())) {
+    if (
+      !trackableState.forceUpdate() &&
+      isEqual(newValue, _storageOption.get())
+    ) {
       return;
     }
     trackableState.set(newValue);