Angular2: how can component bind to class?

Question

I can't find the obvious evidence that how a @Component() binds to a class. How can it know component binds with class RedditArticle instead of class Article? After switching the position of the two class, it is messed up. Does that mean the class we need to bind should followed by the corresponding component?

import { bootstrap } from "angular2/platform/browser";
import { Component } from "angular2/core";

@Component({
    selector: 'reddit-article',
    template: `
        <div class="row">
            <div class="col-md-3"></div>
                <div>Points: {{article.votes}}</div>
            <div class="col-md-9"></div>
                <!--<div class="row">-->
                    Title: {{article.title}}
                    Link: {{article.link}}
                    <button (click)="voteUp()">upvote</button>
                    <button (click)="voteDown()">downvote</button>
                <!--</div>-->
        </div>
    `
})

class RedditArticle {

    article: Article;

    constructor() {
        this.article = new Article('angular2', 'google.com', 0);
    }

    voteUp() {
        this.article.votes++;
    }

    voteDown() {
        this.article.votes--;
    }
}

class Article {
    title: string;
    link: string;
    votes: number;

    constructor(title: string, link: string, votes: number) {
        this.title = title;
        this.link = link;
        this.votes = votes;
    }
}

Answer 1

The @Component() decorator applies directly to the class that follows the annotation.

This is the same for all annotations.

For example

constructor(@Inject('xxx') private val:string, private zone:NgZone) {}

Here @Inject() is bound to val