[IMP] store: make sure set function works with arrays

src/store.ts

@@ -114,18 +114,14 @@ export function makeObserver(): Observer {
   };
 
   function set(target: any, key: number | string, value: any) {
-    if (Array.isArray(target)) {
+    addProp(target, key, value);
-      // todo
-    } else {
-      addProp(target, key as string, value);
-    }
     target.__rev__++;
     observer.__rev__++;
   }
 
   function addProp<T extends { __rev__?: number }>(
     obj: T,
-    key: string,
+    key: string | number,
     value: any
   ) {
     Object.defineProperty(obj, key, {

tests/store.test.ts

@@ -162,6 +162,23 @@ describe("observer", () => {
     expect(ob2.__rev__).toBe(2);
   });
 
+  test("can change values in array", () => {
+    const observer = makeObserver();
+    const obj: any = { arr: [1, 2] };
+
+    observer.observe(obj);
+    expect(obj.arr.__rev__).toBe(0);
+    expect(observer.__rev__).toBe(0);
+
+    obj.arr[0] = "nope";
+    expect(obj.arr.__rev__).toBe(0);
+    expect(observer.__rev__).toBe(0);
+
+    observer.set(obj.arr, 0, "yep");
+    expect(obj.arr.__rev__).toBe(1);
+    expect(observer.__rev__).toBe(1);
+  });
+
   test("various object property changes", () => {
     const observer = makeObserver();
     const obj: any = { a: 1 };