test: adding new tests and improving the reliability of an existing t…

…est (#135)

src/index.spec.ts

@@ -144,6 +144,23 @@ describe('stores', () => {
       ]);
     });
 
+    it('should work to use subscribe only', () => {
+      const store1 = writable(0);
+      const store2 = asReadable({ subscribe: store1.subscribe });
+      expect(store2()).toBe(0);
+      store1.set(1);
+      expect(store2()).toBe(1);
+    });
+
+    it('should work to use subscribe only and use it in a computed', () => {
+      const store1 = writable(0);
+      const store2 = asReadable({ subscribe: store1.subscribe });
+      const store3 = computed(() => store2());
+      expect(store3()).toBe(0);
+      store1.set(1);
+      expect(store3()).toBe(1);
+    });
+
     it('should allow overriding notEqual', () => {
       const notEqualCalls: [number, number][] = [];
       class ModuloStore extends Store<number> {
@@ -765,6 +782,34 @@ describe('stores', () => {
       expect(callCounter).toBe(0);
     });
 
+    it('should call onUse when reading value and using it in computed', () => {
+      const calls: (-1 | 1)[] = [];
+      // eslint-disable-next-line @typescript-eslint/no-unused-vars
+      const readableWithSet = readable(0, (set) => {
+        calls.push(1);
+        return () => {
+          calls.push(-1);
+        };
+      });
+      const dependingStore = computed(() => readableWithSet());
+
+      expect(calls).toEqual([]);
+      expect(readableWithSet()).toBe(0);
+      expect(calls).toEqual([1, -1]);
+      expect(dependingStore()).toBe(0);
+      expect(calls).toEqual([1, -1, 1, -1]);
+      expect(dependingStore()).toBe(0);
+      expect(calls).toEqual([1, -1, 1, -1, 1, -1]);
+      const unsubscribe = dependingStore.subscribe(() => {});
+      expect(calls).toEqual([1, -1, 1, -1, 1, -1, 1]);
+      const unsubscribe2 = dependingStore.subscribe(() => {});
+      unsubscribe();
+      expect(dependingStore()).toBe(0);
+      expect(calls).toEqual([1, -1, 1, -1, 1, -1, 1]);
+      unsubscribe2();
+      expect(calls).toEqual([1, -1, 1, -1, 1, -1, 1, -1]);
+    });
+
     it('should give access to both set and update function in the second argument of the readable shorthand', () => {
       const store = readable(-1, ({ set, update }) => {
         set(0);
@@ -1671,8 +1716,19 @@ describe('stores', () => {
         [visible$, transitioning$],
         ([visible, transitioning]) => !visible && !transitioning
       );
+      const visibleChange = derived([currentlyVisible$, visible$], {
+        equal: () => true,
+        derive([currentlyVisible, visible]) {
+          if (currentlyVisible !== visible) {
+            batch(() => {
+              transitioning$.set(true);
+              currentlyVisible$.set(visible);
+            });
+          }
+        },
+      });
       const state$ = derived(
-        [visible$, transitioning$, hidden$],
+        [visible$, transitioning$, hidden$, visibleChange],
         ([visible, transitioning, hidden]) => {
           if (hidden !== (!visible && !transitioning)) {
             // inconsistent state!!
@@ -1681,17 +1737,6 @@ describe('stores', () => {
           return `visible=${visible},transitioning=${transitioning},hidden=${hidden}`;
         }
       );
-      const visibleChange = derived(
-        [currentlyVisible$, visible$],
-        ([currentlyVisible, visible]) => {
-          if (currentlyVisible !== visible) {
-            batch(() => {
-              transitioning$.set(true);
-              currentlyVisible$.set(visible);
-            });
-          }
-        }
-      );
       const unsubscribeState = state$.subscribe((state) => {
         events.push(`state:${state}`);
       });