node.ts class

最新推荐文章于 2025-04-06 19:40:39 发布

原创最新推荐文章于 2025-04-06 19:40:39 发布 · 182 阅读

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这篇博客探讨了JavaScript中的面向对象编程概念，包括Animal类、Snake和Horse子类的实现，展示了如何使用构造函数和super关键字进行继承。此外，还介绍了Person和Employee类的访问控制，强调了protected和private修饰符在类及其子类中的作用。通过实例展示了类的实例化和方法调用过程。

class Animal {
    name: string;
    constructor(theName: string) { this.name = theName; }
    move(distanceInMeters: number = 0) {
        console.log(`${this.name} moved ${distanceInMeters}m.`);
    }
}

class Snake extends Animal {
    constructor(name: string) { super(name); }
    move(distanceInMeters = 5) {
        console.log("Slithering...");
        super.move(distanceInMeters);
    }
}

class Horse extends Animal {
    constructor(name: string) { super(name); }
    move(distanceInMeters = 45) {
        console.log("Galloping...");
        super.move(distanceInMeters);
    }
}

let sam = new Snake("Sammy the Python");
let tom: Animal = new Horse("Tommy the Palomino");

sam.move();
tom.move(34);

Slithering…
Sammy the Python moved 5m.
Galloping…
Tommy the Palomino moved 34m.

class Person {
    protected name: string;
    constructor(name: string) { this.name = name; }
}

class Employee extends Person {
    private department: string;

    constructor(name: string, department: string) {
        super(name) // 子类构造父类属性，需调用super
        this.department = department;
    }

    public getElevatorPitch() {
        return `Hello, my name is ${this.name} and I work in ${this.department}.`;
    }
}

let howard = new Employee("Howard", "Sales");
console.log(howard.getElevatorPitch());
console.log(howard.name); // 错误,protect属性只能类和子类中访问

class Person {
    protected name: string;
    // 构造函数声明protected属性，表明不能在类外构造对象
    protected constructor(theName: string) { this.name = theName; }
}

// Employee 能够继承 Person
class Employee extends Person {
    private department: string;

    constructor(name: string, department: string) {
        super(name);// 构造父类属性
        this.department = department;
    }

    public getElevatorPitch() {
        return `Hello, my name is ${this.name} and I work in ${this.department}.`;
    }
}

let howard = new Employee("Howard", "Sales");
let john = new Person("John"); // 错误: 'Person' 的构造函数是被保护的.