tknr_y1216

Firestore からのレスポンスに型をつける

<h2 id="firestore-%E3%83%87%E3%83%BC%E3%82%BF%E5%A4%89%E6%8F%9B%E9%96%A2%E6%95%B0%E3%82%92%E5%AE%9A%E7%BE%A9%E3%81%99%E3%82%8B">
<a class="header-anchor-link" href="#firestore-%E3%83%87%E3%83%BC%E3%82%BF%E5%A4%89%E6%8F%9B%E9%96%A2%E6%95%B0%E3%82%92%E5%AE%9A%E7%BE%A9%E3%81%99%E3%82%8B" aria-hidden="true"></a> Firestore データ変換関数を定義する</h2>
<div class="code-block-container"><pre class="language-dart"><code class="language-dart">class TodoEntity {
 final String? id;
 final String? title;
 final Timestamp createdAt;
 final bool? isChecked;
 final bool? isFavorite;

 TodoEntity(
 {this.id,
 this.title,
 required this.createdAt,
 this.isChecked,
 this.isFavorite});

 factory TodoEntity.fromFirestore(
 DocumentSnapshot&lt;Map&lt;String, dynamic&gt;&gt; snapshot,
 SnapshotOptions? options) {
 final data = snapshot.data();

 return TodoEntity(
 id: data?['id'],
 title: data?['title'],
 createdAt: data?['createdAt'],
 isChecked: data?['isChecked'],
 isFavorite: data?['isFavorite'],
 );
 }

 Map&lt;String, dynamic&gt; toFirestore() {
 return {
 if (title != null) "title": title,
 if (title != null) "createdAt": createdAt,
 if (title != null) "isChecked": isChecked,
 if (title != null) "isFavorite": isFavorite,
 };
 }
}
</code></pre></div><iframe id="zenn-embedded__fe239f943e5e7" src="https://embed.zenn.studio/card#zenn-embedded__fe239f943e5e7" data-content="https%3A%2F%2Ffirebase.google.com%2Fdocs%2Ffirestore%2Fquery-data%2Fget-data%3Fhl%3Dja%23custom_objects" frameborder="0" scrolling="no" loading="lazy"></iframe><a href="https://firebase.google.com/docs/firestore/query-data/get-data?hl=ja#custom_objects" style="display:none" target="_blank" rel="nofollow noopener noreferrer">https://firebase.google.com/docs/firestore/query-data/get-data?hl=ja#custom_objects</a>

<h3 id="withconverter-%E3%83%A1%E3%82%BD%E3%83%83%E3%83%89%E3%82%92%E4%BD%BF%E3%81%86%EF%BC%88list%E3%81%AE%E5%A0%B4%E5%90%88%EF%BC%89">
<a class="header-anchor-link" href="#withconverter-%E3%83%A1%E3%82%BD%E3%83%83%E3%83%89%E3%82%92%E4%BD%BF%E3%81%86%EF%BC%88list%E3%81%AE%E5%A0%B4%E5%90%88%EF%BC%89" aria-hidden="true"></a> withConverter メソッドを使う（Listの場合）</h3>
<div class="code-block-container"><pre class="language-dart"><code class="language-dart"> // 全件取得
 Future&lt;List&lt;TodoEntity&gt;&gt; index() async {
 final ref = db
 .collection('todo')
 .orderBy("createdAt", descending: true)
 .withConverter&lt;TodoEntity&gt;(
 fromFirestore: (snapshot, _) =&gt;
 TodoEntity.fromFirestore(snapshot, _),
 toFirestore: (user, _) =&gt; user.toFirestore());

 final snapshot = await ref.get();
 final todos = snapshot.docs
 .map(
 (doc) =&gt; doc.data(),
 )
 .toList();
 return todos;
 }
</code></pre></div>