typeError：对象不是构造函数（正在评估'new _vasern.default'）

Question

Rendering on android

import React from 'react';
import { StyleSheet, View, Text, } from 'react-native';
import Vasern from 'vasern';

const VasernDB = new Vasern({ 
  schemas: [{
     name: "Users",
     props: {
       fname: "string",
       lname: "string"
     }
   },{
     name: "Todos",
     props: {
       name: "string",
       completed: "boolean",
       assignTo: "#Users"
     }
   }],
   version: 1
 });
export default class App extends React.Component {
  render () {
    return (
      <View style={styles.container}>
        <Text>vasern test</Text>              
      </View>
    )
  }
}

可以帮我吗？