javascript - React-navigation error when trying to set up after installing - Element type is invalid -

i new react-native fiddling around , came across need of navigation. however, after following directions on reactnavigation.org emulator spewing out nonsensical error me. google had no sadly time.

element type invalid: expected string (for built-in components) or class/function (for composite components) got: object. forgot export component file it's defined in.

check render method of awakeindevapp.

code simplistic example have:

import react 'react'; import {   appregistry,   text, } 'react-native'; import { stacknavigator } 'react-navigation';  class homescreen extends react.component {   static navigationoptions = {     title: 'welcome',   };   render() {     return <text>hello, navigation!</text>;   } }  const eproj = stacknavigator({   home: { screen: homescreen }, });  appregistry.registercomponent('eproj', () => eproj); 

dependencies:

  "dependencies": {     "expo": "^20.0.0",     "react": "16.0.0-alpha.12",     "react-native": "^0.47.0",     "react-navigation": "^1.0.0-beta.11"   } 

it looks don't need appregistry.registercomponent('eproj', () => eproj); expo try exporting module : export default eproj

here link similar problem