title: Is it better to write my Mobx stores in a separate file or inside the React component?
body: <p>I've seen that you can do something like this:</p>
  
  <pre><code>// App.js
  class App extends Component {
    @observable a = 'something'
  
    @action change() {
      this.a = 'else'
    }
  
    render() {
      return (
        ...
      )
    }
  }
  </code></pre>
  
  <p>And I've also seen that you can write your store in a separate file (which is what I do):</p>
  
  <pre><code>// StoreA.js
  class StoreA {
    @observable a = 'something'
  
    @action change() {
      this.a = 'else'
    }
  }
  
  // App.js
  @observer
  class App extends Component {
    constructor() {
      this.store = new StoreA()
    }
  
    ...
  }
  </code></pre>
  
  <p>Is there any difference between these approaches? Is one better than the other?</p>