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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1.1
Node.js
の「哲学」
3
●
テストや保守が容易になる
●
クライアントとサーバでコードを共有しやすくなる
このように、小さくて単機能なモジュールをもつということは、たとえ小さなコードの断片であって
もそれを共有し再利用するという姿勢を助長し、ひいては
Don't Repeat Yourself
（
DRY
。「自分のやっ
たことを繰り返すな」「同じことを
2
箇所以上に記述するな」）の原則を推し進めることになるのです。
1.1.3
露出部分最小化
モジュールのサイズと担当範囲を最小限にとどめることに加えて、最低限の
API
のみを公開すること
が、モジュール設計時の作法とされています。これにより、モジュールを利用する側にとってわかりや
すく誤解の余地のない
API
を提供できるのです（高度な
API
を提供しても利用されず、一部の
API
しか
利用されないことが多いのです）。
よくあるパターンは、ひとつのモジュールでひとつ
の関数（もしくはコンストラクタ）のみを公開する
というもので、より高度な機能を提供したい場合はオプションとします。こうすることで主要なものと
副次的なものを簡単に区別できます。単一の関数のみを公開することで、間違いの少ない簡潔なエント
リポイントを提供できるのです。
Node
のモジュールは通常、単に利用されるだけで拡張されることはありません。モジュールが拡張
可能でないということは、柔軟性に欠ける印象を与えますが、そもそもモジュールが小さく単機能であ
るため、拡張できなくても問題にはなりません。むしろ
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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.