TypeScript 类
1、类的声明
关键字：class
class Child {}2、类的继承
关键字：extends
class Father{ }class Child extends Father {}3、类与接口
关键字：implments
interface IMan {name: string
}class Father implements IMan {name: stringconstructor(name: string) {this.name = name;}
}class Child extends Father {}let child = new Child("张三");console.log(child.name);// 张三4、抽象类
关键字：abstract
interface IMan {name: string
}abstract class Man {say(): string {return "我是抽象类！"}
}class Father extends Man implements IMan {name: stringconstructor(name: string) {super()this.name = name;}
}class Child extends Father {}let child = new Child("张三");console.log(child.name);
console.log(child.say());// 张三
// 我是抽象类！5、类的成员变量修饰符
公开的：public
私有的：private
受保护的：protected
只读的：readonly
class Man {// 受保护protected gender: string// 只读readonly age: number = 18constructor(gender: string) {this.gender = gender;}
}class Teacher extends Man {// 公开public name: string// 私有private DNA: string = "aaa"getGender(): string {return this.gender;}setGender(gender: string) {this.gender = gender;}constructor(name: string) {super("男");this.name = name;// 可以访问 private属性只能在本类中访问console.log(this.DNA); // aaa // 可以访问 protected属性只能在本类及其子类中访问console.log(this.gender); // 男}
}let teacher = new Teacher("张老师");
// 因为修饰符是public 可以修改和访问
teacher.name = "王老师"
console.log(teacher.name); // 王老师// 报错 因为修饰符是private 所以无法访问
// 属性“DNA”为私有属性，只能在类“Teacher”中访问。
console.log(teacher.DNA);// 报错 因为修饰符是protected
// 属性“gender”受保护，只能在类“Man”及其子类中访问。
console.log(teacher.gender);
// 可以在Man的子类Teacher中进行访问或修改
console.log(teacher.getGender()); // 男
teacher.setGender("女");
console.log(teacher.getGender()); // 女// 报错 只读属性不能修改
// 无法为“age”赋值，因为它是只读属性。
teacher.age = 20;
console.log(teacher.age); // 18
