use localstorage

src/actions.js

@@ -138,15 +138,27 @@ export function changeList(list) {
 export function fetchLists() {
   return async (dispatch) => {
     dispatch(requestLists());
+    const listsJson = localStorage.getItem('lists');
+    let listsObj;
+    try {
+      listsObj = JSON.parse(listsJson);
+    } catch (e) {
+      localStorage.setItem('lists', JSON.stringify({}));
+    }
+    if (listsObj) {
+      dispatch(recieveLists(listsObj));
+      dispatch(changeList(listsObj[Object.keys(listsObj)[0]].id));
+    }
     const response = await fetch(`${API_ROOT}/lists`);
     const json = await response.json();
     const lists = json.data;
-    const listsObj = lists.reduce((obj, list) => {
+    listsObj = lists.reduce((obj, list) => {
       const newObj = { ...obj };
       newObj[list.id] = list;
       return newObj;
     }, {});
     dispatch(recieveLists(listsObj));
     dispatch(changeList(listsObj[Object.keys(listsObj)[0]].id));
+    localStorage.setItem('lists', JSON.stringify(listsObj));
   };
 }