May 2019
Intermediate to advanced
464 pages
9h 22m
Japanese
Content preview from Node.jsデザインパターン 第2版
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297
9
章
特殊な問題を
解決するためのパターン
これまで見てきたデザインパターンはほとんどが一般的なもので、アプリケーション開発のさまざま
な分野で応用できるものでした。しかし、より狭い範囲の、ある程度特殊な問題の解決に使われるパ
ターンもあります。そうしたパターンは「レシピ」と呼ばれます。実際の料理と同様、きちんと決まった
手順があって、期待どおりのものができあがります。もちろん、だからといってお客さんの好みに合わ
せるために創造性を発揮してレシピをカスタマイズしてはいけないというわけではなく、レシピにとっ
て重要なのは手順の「骨子」であるのが普通です。この章では、
Node
開発で遭遇する問題のうち、特
定のものを解決する人気のあるレシピを紹介していきます。次のようなレシピです。
●
非同期に初期化されるモジュールを
require
する方法
●
非同期処理にバッチ処理やキャッシングを追加することで、計算量の大き
いアプリケーションの
パフォーマンスを最小限の手間で大きく向上させる方法
●
CPU
バウンドな同期処理の効率を上げるための手法
9.1
非同期に初期化されるモジュールの
require
2
章で
Node
のモジュールシステムの基本的な特性を説明した際に、
require()
は同期的に実行さ
れ、
module.exports
を非同期に設定することはできないと述べました。
これが、コアモジュールや多くの
npm
パッケージに同期的
API
が存在する主な理由のひとつで、非
同期
API
の代わりに使うのではなく、主に初期化 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.