feat: Array.prototype.{findLast, findLastIndex}の追加 #1675
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azu
commented
Jun 25, 2023
source/basic/array/README.md
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| @@ -296,6 +302,8 @@ console.log(indexOfBlue); // => 2 | |||
| console.log(colors[indexOfBlue]); // => { "color": "blue" } | |||
| ``` | |||
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| Arrayの`findIndex`にも対となる`findLastIndex`メソッドがあり、`findLastIndex`メソッドは末尾から検索した結果が得られます。 | |||
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サンプルコードを入れたい気もするが、なくても大丈夫という気もする。
一つ思いついたのは、最初に記録された日と最後に記録された日をfindとfindLastで探すという例。
これが何の記録かというのがいまいち思いつかなかった。
[{ date: "2023-06-01", count: 1},{ date: "2023-06-10", count: 10}, { date: "2023-06-25", count: 15}]
Signed-off-by: azu <azuciao@gmail.com>
Signed-off-by: azu <azuciao@gmail.com>
azu
changed the title
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概要
ES2023では、
Array.prototype.findIndexとArray.prototype.findに対応するメソッドとして、Array.prototype.findLastIndexとArray.prototype.findLastが追加されました。それぞれ
indexOfとlastIndexOfと同様に、末尾から探索した結果を返すメソッドになっています。変更されたページ
変更点
Array.prototype.findLastIndexとArray.prototype.findLastの対応Array.prototype.lastIndexOfのサンプルコードを追加関連