一、类的定义

二、对象的创建

class Person{id:number;name:string;age:number = 18;constructor(id:number,name:string){this.id = id;this.name = name;}introduce():string{return `hello,I am ${this.name},and I am ${this.age} years old.`}
}let person = new Person(1,'zhangsan');console.log(person)

三、静态成员

声明静态成员 使用static关键字，静态成员隶属于类本身，而不属于某个对象实例

class Constants{static count:number = 1;
}class Utils{static toLowerCase(str:string){return str.toLowerCase();}
}console.log(Constants.count);console.log(Utils.toLowerCase("Hello World"))

四、类的继承

继承是面向对象编程中的重要机制，允许一个类(子类或派生类)继承另一个(父类或基类)的属性和方法。子类可以直接使用父类的特性，并根据需要添加新的特性或覆盖现有的特性。

class Person{id:number;name:string;age:number = 18;constructor(id:number,name:string){this.id = id;this.name = name;}introduce():string{return `hello,I am ${this.name},and I am ${this.age} years old.`}
}class Student extends Person{classNumber:string;constructor(id:number,name:string,classNumber:string){super(id,name);this.classNumber = classNumber;}introduceSTU():string{return `hello,I am ${this.name},and I am ${this.age} years old.I am a student`}
}let student = new Student(1,'zhangsan','aaa');console.log(student.introduceSTU());

4.1 访问修饰符

主要用于控制类成员的可访问性

 五、接口

5.1 接口的定义

通常情况下接口只会包含属性和方法的声明，而不包含具体的实现细节，具体的细节由其实现类完成

interface Person{id:number;name:string;age:number;introduce():void;
}

5.2 接口的实现

interface Person{id:number;name:string;age:number;introduce():void;
}class Stu implements Person{id:number;name:string;age:number;constructor(id:number,name:string,age:number){this.id = id;this.name = name;this.age = age;}introduce():void{console.log("Hello zzm")}
}let s1 = new Stu(1,'zzm',1);console.log(s1.introduce())

六、多态

多态可以使同一类型的对象具有不同的行为

interface Person{id:number;name:string;age:number;introduce():void;
}class Stu implements Person{id:number;name:string;age:number;constructor(id:number,name:string,age:number){this.id = id;this.name = name;this.age = age;}introduce():void{console.log("Hello stu")}
}class Tea implements Person{id:number;name:string;age:number;constructor(id:number,name:string,age:number){this.id = id;this.name = name;this.age = age;}introduce():void{console.log("Hello,tea")}
}let s1 = new Stu(1,'zzm',1);
let t1 = new Tea(1,"zzm",1);s1.introduce();
t1.introduce();