fix(overmind): deep clone state on app creation

this avoids bugs when some parts of a configuration state are reused

Author: gaspard

packages/node_modules/overmind/src/index.ts

@@ -1,22 +1,23 @@
 import { ActionChain } from 'action-chain'
 import { EventEmitter } from 'betsy'
 import ProxyStateTree from 'proxy-state-tree'
-import Derived from './derived'
-import Devtools, { Message, safeValue } from './Devtools'
+
 import ActionClass, {
-  IValueAction,
-  INoValueAction,
   Compose,
+  INoValueAction,
+  IValueAction,
   createOperators,
 } from './Action'
-import Reaction from './reaction'
+import Derived from './derived'
+import Devtools, { Message, safeValue } from './Devtools'
 import {
   DynamicModule,
-  SubType,
-  Events,
   EventType,
+  Events,
   Options,
+  SubType,
 } from './internalTypes'
+import Reaction from './reaction'
 
 export { IValueAction, Compose, EventType }
 
@@ -529,8 +530,14 @@ export default class App<
   }
   private processState(state: {}) {
     return Object.keys(state).reduce((aggr, key) => {
-      aggr[key] =
-        typeof state[key] === 'function' ? new Derived(state[key]) : state[key]
+      const value = state[key]
+      if (typeof value === 'object') {
+        aggr[key] = this.processState(value)
+      } else if (typeof value === 'function') {
+        aggr[key] = new Derived(value)
+      } else {
+        aggr[key] = value
+      }
 
       return aggr
     }, {})