React Native simple mobx

index.js

import React from 'React';
import { View, Button, Text } from 'react-native';
import { observable, computed, action } from 'mobx';
import { observer } from 'mobx-react';

class _TodosService {
  i = 1
  @observable todos = [
    {name: "Test_0", done: false}
  ]

  @computed get todosList() {
    return this.todos
  }

  @action addTodo() {
    this.todos.push({name: "Test_" + this.i++, done: false})
  }
}
const TodosService = new _TodosService();

@observer
export default class App extends React.Component {
  render() {
    return (
      <View style={{paddingTop: 30}}>
        <Button onPress={ () => TodosService.addTodo() }>
          <Text>Add todos</Text>
        </Button>

        <Text>{ JSON.stringify( TodosService.todosList ) }</Text>
      </View>
    )
  }
}