title: Access Method from Vue Class Component Decorator inside a Watcher
body: <p>Essentially i have the same question as <a href="https://github.com/vuejs/vue-class-component/issues/426" rel="nofollow noreferrer">this</a> and <a href="https://github.com/vuejs/vue-class-component/issues/442" rel="nofollow noreferrer">this</a> issue on Github, which unfortunately were both closed before being answered :/</p>
  <p>I am using Vue with Typscript and the Vue Class Components.
  What i need to do is to access a method of my (Vue-) Class from inside a watcher inside the @Component decorator.
  I know that it's possible to access the data of a component with <code>this.$data</code>, but what about methods.</p>
  <p>My code works on runtime but produces compiletime-errors and errors in vscode (&quot;Property 'clearInfo' does not exist on type 'Vue'.&quot;);</p>
  <pre><code>@Component({
    watch: {
      firstMesh(newMesh) {
        if (newMesh === undefined) this.clearInfo(1);   // this produces the errors
        else this.showMeshInfo(newMesh, 1);
      },
      secondMesh(newMesh) {
        if (newMesh === undefined) this.clearInfo(2);
        else this.showMeshInfo(newMesh, 2);
      },
    },
  })
  
  
  export default class Info extends Vue {
    clearInfo(whichMesh : number) {
  ...
    }
  
    showMeshInfo(mesh : any, index : number) {
      ....
    }
  
  
  }
  </code></pre>