[解決済み] Angular 2で簡単なアコーディオンを作成するにはどうすればよいですか？

質問

以前は、この簡単なスクリプトを使って、簡単なアコーディオンを作っていました。

(function() { 

    $('dl.accordion').on('click', 'dt', function() {
        this_= $(this);
        this_
            .addClass("selected")
            .next()
                .slideDown(200)
                .siblings('dd')
                    .slideUp(200);
        this_.siblings()
            .removeClass("selected")

    });
})();

そして、このhtml

<dl class="accordion">
    <dt>What are your hours?</dt>
    <dd>We are open 24/7.</dd>
    <dt>What are your hours?</dt>
    <dd>We are open 24/7.</dd>
</dl>

では、Angular 2で書かれたこのコードのコピーを作りたいと思います。

Angular 2で上記のようなシンプルなアコーディオンを作成するにはどうすればよいですか？

レンダラー、elementRefなどを学ばなければならないのでしょうね。 これを作成するために学ぶべき他のトピックを提案することができますか？

どのように解決するのですか？

これは非常にシンプルなアコーディオンです。

app/accordion.component.ts

import { Component, Input, Output, EventEmitter } from '@angular/core';

@Component({
  selector: 'tp-accordion',
  template: `
    <h2 class="accordion-head" (click)="onClick($event)">{{ title }}</h2>
    <div class="accordion-body" [class.active]="active">
      <ng-content></ng-content>
    </div>
  `,
  styles: [
    `
    .accordion-head {
      cursor: pointer;
    }
    .accordion-body {
      display: none;
    }
    .accordion-body.active {
      display: block;
      -webkit-animation: fadeIn .3s;
      animation: fadeIn .3s;
    }
    @-webkit-keyframes fadeIn {
      from { opacity: 0; transform: scale(0); }
        to { opacity: 1; transform: scale(1); }
    }  
    @keyframes fadeIn {
      from { opacity: 0; transform: scale(0); }
        to { opacity: 1; transform: scale(1); }
    }
    `  
  ],
})
export class Accordion {

  @Input() title: string;

  @Input() active: boolean = false;

  @Output() toggleAccordion: EventEmitter<boolean> = new EventEmitter();

  constructor() {}

  onClick(event) {
    event.preventDefault();
    this.toggleAccordion.emit(this.active);
  }

}

app/accordion-group.component.ts

import { Component, ContentChildren, QueryList, AfterContentInit, OnDestroy } from '@angular/core';

import { Accordion } from './accordion.component';

@Component({
  selector: 'tp-accordion-group',
  template: `
    <ng-content></ng-content>
  `
})
export class AccordionGroup {

  @ContentChildren(Accordion) accordions: QueryList<Accordion>;
  private subscriptions = [];

  private _accordions = [];

  constructor() {}

  ngAfterContentInit() {

    this._accordions = this.accordions;
    this.removeSubscriptions();
    this.addSubscriptions();

    this.accordions.changes.subscribe(rex => {
      this._accordions = rex;
      this.removeSubscriptions();
      this.addSubscriptions();
    });
  }

  addSubscriptions() {
    this._accordions.forEach(a => {
      let subscription = a.toggleAccordion.subscribe(e => {
        this.toogleAccordion(a);
      });
      this.subscriptions.push(subscription);
    });
  }

  removeSubscriptions() {
    this.subscriptions.forEach(sub => {
      sub.unsubscribe();
    });
  }

  toogleAccordion(accordion) {
    if (!accordion.active) {
      this.accordions.forEach(a => a.active = false);
    }
    // set active accordion
    accordion.active = !accordion.active;
  }

  ngOnDestroy() {
    this.removeSubscriptions();
  }

}

app/app.component.ts

import { Component, OnInit, OnDestroy } from '@angular/core';
import { PostsService } from './posts.service';


@Component({
  selector: 'app-root',
  template: `
    <tp-accordion-group>
      <tp-accordion *ngFor="let post of posts" [title]="post.title">
        {{ post.body }}
      </tp-accordion>
    </tp-accordion-group>
  `
})
export class AppComponent implements OnInit, OnDestroy {

  posts = [];
  private subscription: any;

  constructor(private postsSvc: PostsService) {}

  ngOnInit() {
    this.subscription = this.postsSvc.getPosts().subscribe(res => {
      if (res.length) {
        this.posts = res.slice(0, 10);
      }
    })
  }

  ngOnDestroy() {
    if (this.subscription) {
      this.subscription.unsubscribe();
    }
  }

}

app/posts.service.ts

import { Injectable } from '@angular/core';
import { Http } from '@angular/http';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';

@Injectable()
export class PostsService {
  postsUrl: 'https://jsonplaceholder.typicode.com/posts';
  constructor(private http: Http) {

  }
  getPosts() {
    return this.http.get(this.postsUrl)
      .map(res => {
        let body = res.json();
        return body || [];
      })
      .catch(console.log);
  }
}

オンラインデモの様子。 https://plnkr.co/edit/xFBllK?p=preview

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