Small fix on mergeDeep strategy for persistence rehydration

src/computed-properties.js

@@ -1,3 +1,46 @@
+import memoizerific from 'memoizerific';
+import { get } from './lib';
+import { computedSymbol } from './constants';
+
+export function createComputedPropertyBinder(
+  parentPath,
+  key,
+  definition,
+  computedState,
+  references,
+) {
+  const computedMeta = definition[computedSymbol];
+  const memoisedResultFn = memoizerific(1)(definition);
+  return function createComputedProperty(o) {
+    Object.defineProperty(o, key, {
+      configurable: true,
+      enumerable: true,
+      get: () => {
+        let storeState;
+        if (computedState.isInReducer) {
+          storeState = computedState.currentState;
+        } else if (references.getState == null) {
+          return undefined;
+        } else {
+          try {
+            storeState = references.getState();
+          } catch (err) {
+            if (process.env.NODE_ENV !== 'production') {
+              console.warn('Invalid access attempt to a computed property');
+            }
+            return undefined;
+          }
+        }
+        const state = get(parentPath, storeState);
+        const inputs = computedMeta.stateResolvers.map(resolver =>
+          resolver(state, storeState),
+        );
+        return memoisedResultFn(...inputs);
+      },
+    });
+  };
+}
+
 export function createComputedPropertiesMiddleware(references) {
   return store => next => action => {
     references.internals.computedState.currentState = store.getState();

src/extract-data-from-model.js

@@ -13,7 +13,7 @@ import { extractPersistConfig } from './persistence';
 import { createActionCreator } from './actions';
 import { createThunkHandler, createThunkActionsCreator } from './thunks';
 import { bindListenerDefinitions } from './listeners';
-import { createComputedPropertyBinder } from './computed';
+import { createComputedPropertyBinder } from './computed-properties';
 
 export default function extractDataFromModel(
   model,

src/persistence.js

@@ -197,6 +197,12 @@ export function rehydrateStateFromPersistIfNeeded(
             Object.keys(currentNext).forEach(key => {
               const data = currentNext[key];
               if (typeof data === 'object') {
+                if (
+                  currentTarget[key] == null ||
+                  typeof currentTarget[key] !== 'object'
+                ) {
+                  currentTarget[key] = {};
+                }
                 setAt(currentTarget[key], data);
               } else {
                 currentTarget[key] = data;