abort setting state when component got unmounted

Author: rwieruch

src/useDataApiHook-example/index.js

@@ -39,19 +39,29 @@ const useDataApi = (initialUrl, initialData) => {
   });
 
   useEffect(() => {
+    let didCancel = false;
+
     const fetchData = async () => {
       dispatch({ type: 'FETCH_INIT' });
 
       try {
         const result = await axios(url);
 
-        dispatch({ type: 'FETCH_SUCCESS', payload: result.data });
+        if (!didCancel) {
+          dispatch({ type: 'FETCH_SUCCESS', payload: result.data });
+        }
       } catch (error) {
-        dispatch({ type: 'FETCH_FAILURE' });
+        if (!didCancel) {
+          dispatch({ type: 'FETCH_FAILURE' });
+        }
       }
     };
 
     fetchData();
+
+    return () => {
+      didCancel = true;
+    };
   }, [url]);
 
   const doGet = (event, url) => {