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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26
2
章
Node.js
の基本パターン
このパターンでは
JavaScript
の関数がプライベートなスコープを形成するという性質を利用して、必
要なものだけを公開します。上のコードでは変数
module
には公開された
API
だけが含まれており、そ
の他の変数や関数（
privateFoo
および
privateBar
）は外部からアクセスできません。下で説明する
ように、このパターンの背後にあるアイデアが、
Node
のモジュールシステムの基盤を形成しています。
2.2.2
Node.js
モジュールシステムの詳細
JavaScript
の標準化を目指す
CommonJS
というグループがあり、
CommonJS
モジュールを公開して
います。
Node
のモジュールシステムは、この
CommonJS
モジュールを独自に拡張したものとなってい
ます。上で説明した公開モジュールパターンと同じように、
Node
のモジュールは自身のスコープをも
ち、モジュール内部での変数定義がグローバルス
コープを汚染しないようになっています。
2.2.2.1
自作のモジュールローダ
モジュールシステムを理解するために、ゼロから簡単なものを作ってみましょう。
Node
の関数
require()
のサブセットを実装します。
まずはひとつ関数を作ります。この関数はモジュールの中身をロードして、プライベートなスコープ
にラップし、それを評価します（
10_module_loader
）。
function loadModule(filename, module, require) ...
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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.
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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.