Angular2 - angular2.dev.js:23501 EXCEPTION: No Directive annotation found on ArticleComponent

Question

I'm following ng-book2 in writing a simple reddit clone app. So far all I have is a index.html file and a single app.ts file.

Now in my app.ts file, I declare 2 components. The second component - reddit is supposed to load the first component - reddit-article and the Article class. Now upon running the server I get the following error:

angular2.dev.js:23501 EXCEPTION: No Directive annotation found on ArticleComponentBrowserDomAdapter.logError @ angular2.dev.js:23501BrowserDomAdapter.logGroup @ angular2.dev.js:23512ExceptionHandler.call @ angular2.dev.js:1185(anonymous function) @ angular2.dev.js:12489NgZone._notifyOnError @ angular2.dev.js:13533collection_1.StringMapWrapper.merge.onError @ angular2.dev.js:13437Zone.run @ angular2-polyfills.js:1247(anonymous function) @ angular2.dev.js:13456zoneBoundFn @ angular2-polyfills.js:1220lib$es6$promise$$internal$$tryCatch @ angular2-polyfills.js:468lib$es6$promise$$internal$$invokeCallback @ angular2-polyfills.js:480lib$es6$promise$$internal$$publish @ angular2-polyfills.js:451(anonymous function) @ angular2-polyfills.js:123microtask @ angular2.dev.js:13488Zone.run @ angular2-polyfills.js:1243(anonymous function) @ angular2.dev.js:13456zoneBoundFn @ angular2-polyfills.js:1220lib$es6$promise$asap$$flush @ angular2-polyfills.js:262 angular2.dev.js:23501 STACKTRACE:BrowserDomAdapter.logError @ angular2.dev.js:23501ExceptionHandler.call @ angular2.dev.js:1187(anonymous function) @ angular2.dev.js:12489NgZone._notifyOnError @ angular2.dev.js:13533collection_1.StringMapWrapper.merge.onError @ angular2.dev.js:13437Zone.run @ angular2-polyfills.js:1247(anonymous function) @ angular2.dev.js:13456zoneBoundFn @ angular2-polyfills.js:1220lib$es6$promise$$internal$$tryCatch @ angular2-polyfills.js:468lib$es6$promise$$internal$$invokeCallback @ angular2-polyfills.js:480lib$es6$promise$$internal$$publish @ angular2-polyfills.js:451(anonymous function) @ angular2-polyfills.js:123microtask @ angular2.dev.js:13488Zone.run @ angular2-polyfills.js:1243(anonymous function) @ angular2.dev.js:13456zoneBoundFn @ angular2-polyfills.js:1220lib$es6$promise$asap$$flush @ angular2-polyfills.js:262 angular2.dev.js:23501 Error: No Directive annotation found on ArticleComponent at new BaseException (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:7385:21) at DirectiveResolver.resolve (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:6688:13) at RuntimeMetadataResolver.getDirectiveMetadata (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:22724:47) at http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:22792:22 at Array.map (native) at Array.map (http://localhost:8080/node_modules/es6-shim/es6-shim.js:1101:14) at RuntimeMetadataResolver.getViewDirectivesMetadata (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:22791:25) at TemplateCompiler._compileNestedComponentRuntime (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:24763:63) at http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:24748:26 at Array.forEach (native)

-----async gap----- Error at _getStacktraceWithUncaughtError (http://localhost:8080/node_modules/angular2/bundles/angular2-polyfills.js:2244:29) at Zone.fork (http://localhost:8080/node_modules/angular2/bundles/angular2-polyfills.js:2293:47) at Zone.bind (http://localhost:8080/node_modules/angular2/bundles/angular2-polyfills.js:1218:53) at bindArguments (http://localhost:8080/node_modules/angular2/bundles/angular2-polyfills.js:1401:36) at lib$es6$promise$promise$$Promise.obj.(anonymous function) [as then] (http://localhost:8080/node_modules/angular2/bundles/angular2-polyfills.js:1413:46) at TemplateCompiler._compileComponentRuntime (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:24741:14) at TemplateCompiler.compileHostComponentRuntime (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:24693:14) at RuntimeCompiler_.compileInHost (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:25044:37) at DynamicComponentLoader_.loadAsRoot (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:12253:29) at di_1.provide.useFactory (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:12351:39)

-----async gap----- Error at _getStacktraceWithUncaughtError (http://localhost:8080/node_modules/angular2/bundles/angular2-polyfills.js:2244:29) at Zone.fork (http://localhost:8080/node_modules/angular2/bundles/angular2-polyfills.js:2293:47) at NgZone._createInnerZone (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:13444:39) at new NgZone (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:13310:32) at createNgZone (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:12373:12) at PlatformRef_.application (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:12448:31) at Object.bootstrap (http://localhost:8080/node_modules/angular2/bundles/angular2.dev.js:25239:64) at execute (http://localhost:8080/app.js:76:23) at ensureEvaluated (http://localhost:8080/node_modules/systemjs/dist/system.src.js:2981:26) at Object.execute (http://localhost:8080/node_modules/systemjs/dist/system.src.js:3099:13)

index.html:

<!doctype html>
<html>
  <head>
    <title>Angular 2 - Simple Reddit</title>
    <link rel="icon" type="image/png" href="resources/images/favicon-32x32.png" sizes="32x32" />
    <link rel="icon" href="resources/images/favicon.ico" />
    <!-- Libraries -->
    <script src="node_modules/es6-shim/es6-shim.js"></script>
    <script src="node_modules/angular2/bundles/angular2-polyfills.js"></script>
    <script src="node_modules/systemjs/dist/system.src.js"></script>
    <script src="node_modules/rxjs/bundles/Rx.js"></script>
    <script src="node_modules/angular2/bundles/angular2.dev.js"></script>

    <!-- Stylesheet -->
    <link rel="stylesheet" type="text/css" href="resources/vendor/semantic.min.css">
    <link rel="stylesheet" type="text/css" href="styles.css">
  </head>
  <body>

    <!-- Configure System.js, our module loader -->
    <script>
      System.config({
        packages: {        
          app: {
            format: 'register',
            defaultExtension: 'js'
          }
        }
      });
      System.import('app.js')
            .then(null, console.error.bind(console));
    </script>

    <!-- Menu Bar -->
    <div class="ui menu">
      <div class="ui container">
        <a href="#" class="header item">
          <img class="logo" src="resources/images/ng-book-2-minibook.png">
          ng-book 2
        </a>
        <div class="header item borderless">
          <h1 class="ui header">
            Angular 2 Simple Reddit
          </h1>
        </div>
      </div>
    </div>

    <div class="ui main text container">
      <reddit>Loading...</reddit> <!-- <--- Our app loads here! -->
    </div>

  </body>
</html>

app.ts:

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

@Component({
  selector: 'reddit-article',
  host: {
    class: 'row'
  },
  template: `
<div class="four wide column center aligned votes"> <div class="ui statistic">
<div class="value"> {{ article.votes }}
</div>
<div class="label">
Points
        </div>
      </div>
</div>
<div class="twelve wide column">
<a class="ui large header" href="{{ article.link }}"> {{ article.title }}
</a>
<ul class="ui big horizontal list voters">
<li class="item">
<a href (click)="voteUp()">
<i class="arrow up icon"></i> upvote
</a> </li>
<li class="item">
<a href (click)="voteDown()">
<i class="arrow down icon"></i>
downvote
</a> </li>
</ul> </div>
`
})

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

  constructor(title: string, link: string, votes?: number) {
    this.title = title;
    this.link = link;
    this.votes = votes || 0;
  }

  voteUp(): void {
    this.votes += 1;
  }

  voteDown(): void {
    this.votes -= 1;
  }
}

class ArticleComponent {
  article: Article;

  constructor() {
    this.article = new Article('Angular 2', 'http://angular.io', 10);
  }

  voteUp(): boolean {
    this.article.voteUp();
    return false;
  }

  voteDown(): boolean {
    this.article.voteDown();
    return false;
  }
}

@Component({
  selector: 'reddit',
  directives: [ArticleComponent],
  template: `
    <form class="ui large form segment">
      <h3 class="ui header">Add a Link</h3>
<div class="field">
<label for="title">Title:</label> <input name="title" #newtitle>
      </div>
      <div class="field">
        <label for="link">Link:</label>
        <input name="link" #newlink>
</div>
      <button (click)="addArticle(newtitle, newlink)"
              class="ui positive right floated button">
        Submit link
      </button>
</form> 
<div class="ui grid posts">
  <reddit-article>
  </reddit-article>
</div>`
})

class RedditApp {
  constructor() {
  }
  addArticle(title: HTMLInputElement, link: HTMLInputElement): void {
    console.log(`Adding article title: ${title.value} and link: ${link.value}`);
  }
}

bootstrap(RedditApp);

Answer 1

You list ArticleComponent in directives of RedditApp but ArticleComponent isn't a directive. It doesn't have a @Directive(...) or @Component(...) decorator.

Answer 2

You define the @Component on the wrong class: Article instead of ArticleComponent. You set the ArticleComponent class within the directives attribute of the RedditApp class.

You could change this this way:

class Article {
  (...)
}

@Component({
  (...)
})
class ArticleComponent {
  (...)
}

@Component({
  (...)
})
class RedditApp {
  (...)
}