ts extends詳細用法

TypeScript 的 extends 關鍵字允許將屬性和方法從基底類別繼承到衍生類別。雖然有利於程式碼重用和多態性，但它也有缺點，例如缺乏多重繼承、緊密耦合和抽象 l

如何利用 extends 關鍵字繼承 TypeScript 中的功能和屬性？

In TypeScript 中，extends 關鍵字用於建立從基底類別（或父類別）繼承屬性和方法的衍生類別（或子類別）。若要使用 extends 關鍵字繼承基底類，可以依照下列步驟操作：extends keyword is used to create a derived class (or child class) that inherits properties and methods from a base class (or parent class). To inherit from a base class using the extends keyword, you can follow these steps:

1. Define the base class with its properties and methods.
2. Use the extends keyword to define a derived class, specifying the base class as the parent class.
3. Access the properties and methods of the base class within the derived class using the super keyword.

For example, consider the following base class:

<code>class Animal {
  name: string;
  age: number;

  constructor(name: string, age: number) {
    this.name = name;
    this.age = age;
  }

  speak() {
    console.log("Animal speaks");
  }
}</code>

To create a derived class that inherits from the Animal class, we can use the extends keyword as follows:

<code>class Dog extends Animal {
  breed: string;

  constructor(name: string, age: number, breed: string) {
    super(name, age);  // Call the base class constructor
    this.breed = breed;
  }

  speak() {
    console.log("Dog barks");
  }
}</code>

In the Dog class, we extend the Animal class, inheriting its properties and methods. We can access the name and age properties inherited from the Animal class using the super keyword, and we can also define new properties and methods specific to the Dog class, such as the breed property and the speak method.

What are the drawbacks and limitations of using the extends keyword in TypeScript?

The extends keyword in TypeScript is a powerful tool for inheriting functionality and properties from a base class, but it also has some drawbacks and limitations to consider:

• Multiple inheritance is not supported: TypeScript does not support multiple inheritance, which means that a derived class can only inherit from a single base class.
• Tight coupling: Classes that use the extends keyword are tightly coupled to their base classes. Changes made to the base class can affect the derived class, potentially breaking its functionality.
• Lack of abstraction: Derived classes that rely heavily on the implementation details of their base classes can lack abstraction, making it difficult to maintain and extend the codebase.

When and why should I prefer using the extends keyword over other inheritance mechanisms in TypeScript?

The extends

定義基底類別及其屬性和方法。

• 使用 extends 關鍵字定義派生類，指定基底類別為父類。
• 在衍生類別中使用 super 關鍵字存取基底類別的屬性和方法。
• 例如，考慮以下基類：
rrreee

rrreee

• 有哪些缺點和在 TypeScript 中使用 extends 關鍵字的限制？
• TypeScript 中的extends 關鍵字是從基類繼承功能和屬性的強大工具，但它也有一些缺點和限制需要考慮：

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