seivan · April 12, 2020 08:02 · Apr 12, 2020
diff --git a/app.tsx b/app.tsx
@@ -0,0 +1,18 @@
+const WithJustAutoRun = React.memo((props: {
+  first: Todo;
+  second: Todo;
+  counter: number;
+}) => {
+
+  const rendered = useObservation(() => {
+    return (
+      <div>
+        <h1>
+          Obs: {props.counter.toString() + props.first.completed.toString()}
+        </h1>
+      </div>
+    );
+  }, [props]);
+
+  return <div>{rendered}</div>;
+})
diff --git a/lib.tsx b/lib.tsx
@@ -0,0 +1,17 @@
+const useObservation = (
+  render: () => JSX.Element,
+  dependencies: React.DependencyList = []
+) => {
+  const ref = useRef<JSX.Element>();
+  const [tick, setTick] = useState(0);
+
+  useEffect(() => {
+    return autorun(() => {
+      ref.current = render();
+      setTick(tick + 1);
+    });
+  }, dependencies);
+
+  return ref.current;
+};
+