TypeScript uses structural subtyping, so anything whose shape matches can be passed straight through without an explicit implements. This chapter looks at where the need for a converter in between still remains.
An object with many optional arguments can be assembled from a literal. An ordering constraint such as "you cannot build until this value is set" is something TypeScript's types can express.
The structure of handing a request along step by step is widely used as middleware in Node.js. This chapter goes as far as building context up through types.
In this chapter, you learn the basics of how to write classes in TypeScript.
When you handle a tree, a recursive discriminated union can stand in for a class hierarchy built on a shared interface. The subject here is a file system.
Despite the shared name, GoF's Decorator pattern and TypeScript's Decorators syntax are different concepts. This chapter separates the two, then compares the pattern with composition through higher-order functions.
In TypeScript, pulling creation logic out usually needs nothing more than a plain function and a union of literal types. Abstract Factory only earns its place when a constraint ties several related products together.
In this chapter, you learn about class inheritance and interfaces in TypeScript.
The abstraction of iteration is in the language specification as Symbol.iterator and generators. This chapter checks whether any reason remains to write an Iterator class of your own.
Before you build a notification mechanism of your own, there are standard tools: EventTarget and AbortSignal. This chapter looks at how far the standard gets you, unsubscription included.
PHP でクラス設計そのものを入門から実践まで学ぶ全14章のガイド。フレームワーク非依存の設計原則 (カプセル化・単一責任・継承とコンポジション・インターフェース・SOLID) から、Laravel でのモデル/サービスクラス設計まで一気通貫で扱います。
PHPにおけるクラスの基本文法。プロパティ・メソッド・コンストラクタ・可視性修飾子・readonly・コンストラクタプロモーション・enumを解説します。
JavaScript has a built-in object called Proxy, and it is not the same thing as GoF's Proxy pattern. This chapter covers both, using lazy loading and access logging as its subjects.
Repository comes from PoEAA, not GoF. To avoid overlapping with the existing articles, this chapter narrows to how TypeScript's types express this boundary.
An ES module is evaluated only once as long as it resolves to the same URL, so you get a single instance without writing a Singleton class. This chapter maps how far that guarantee reaches and when you still need another approach.
Instead of a class per state, representing states with a discriminated union lets the type forbid operations the current state cannot accept. The subject here is a vending machine.
If all you do is swap behavior, passing a function is enough. What still makes you want to bundle things into an object is a strategy that carries several methods or state.
A short take on the eight patterns that got no chapter of their own, plus every judgment in the series collected into one table. It also lays out the steps for deciding whether to use a pattern.
Inheriting from an abstract class is not the only way to fix the skeleton of a procedure and swap out one part of it. This chapter sorts out how that differs from taking hook functions.
A 16-chapter guide that rereads the 23 GoF patterns in modern TypeScript. Each chapter judges whether language features can replace the pattern, and lays out the conditions under which writing it as a class still pays off.
With an exhaustiveness check built from a discriminated union and never, the type prevents forgotten cases without assembling Visitor's class hierarchy. The subject here is a syntax tree.
インターフェースによる契約に基づく設計と、依存性逆転の原則という考え方を解説します。
public propertyの危険性、tell-don't-ask原則、ゲッター・セッターの要否判断を解説します。
Strategy・Singleton・Observer・Abstract Factory の 4 パターンを、それぞれが解こうとした問題から解説します。Strategy と State、Observer とポーリング、Abstract Factory と Factory Method といった混同されやすい組み合わせの区別を扱います。
PHPクラス設計ガイド連載の第1章。god classや変更に弱いコードの実例を通じて、クラス設計を学ぶ意味と連載全体の見通しを示します。
第1部の集大成として、開放閉鎖・リスコフ置換・インターフェース分離の原則を補い、凝集度と結合度という物差しでこれまでの原則を振り返ります。
単一責任の原則とクラスを小さく保つ考え方。god classの兆候と、責務分割の実例を解説します。
is-a・has-aの関係と、なぜ継承よりコンポジションが優先されるかを解説します。