Fixes the error on app exiting on via the device back button

components/app.js

@@ -14,7 +14,7 @@ import { isSymptomView, isSettingsView } from './pages'
 
 import { headerTitles } from '../i18n/en/labels'
 import setupNotifications from '../lib/notifications'
-import { getCycleDay } from '../db'
+import { getCycleDay, closeDb } from '../db'
 
 class App extends Component {
 
@@ -30,12 +30,25 @@ class App extends Component {
 
     this.backHandler = BackHandler.addEventListener(
       'hardwareBackPress',
-      props.goBack
+      this.goBack
     )
 
     setupNotifications(this.props.navigate)
   }
 
+  goBack = () => {
+    const { currentPage } = this.props.navigation
+
+    if (currentPage === 'Home') {
+      closeDb()
+      BackHandler.exitApp()
+    } else {
+      this.props.goBack()
+    }
+
+    return true
+  }
+
   componentWillUnmount() {
     this.backHandler.remove()
   }

slices/navigation.js

@@ -1,7 +1,5 @@
 import { createSlice } from 'redux-starter-kit'
 import { pages, isSymptomView } from '../components/pages'
-import { closeDb } from '../db'
-import { BackHandler } from 'react-native'
 
 const navigationSlice = createSlice({
   slice: 'navigation',
@@ -17,12 +15,6 @@ const navigationSlice = createSlice({
     },
     goBack: ({ currentPage, previousPage }) => {
 
-      if (currentPage === 'Home') {
-        closeDb()
-        BackHandler.exitApp()
-        return { currentPage }
-      }
-
       if (currentPage === 'CycleDay' || isSymptomView(currentPage)) {
         if (previousPage) {
           return {
@@ -33,7 +25,8 @@ const navigationSlice = createSlice({
 
       const page = pages.find(p => p.component === currentPage)
       return {
-        currentPage: page.parent
+        currentPage: page.parent,
+        previousPage: currentPage,
       }
     }
   }