类

class People {
  hi:string
  constructor(message:string){
    this.hi = message
  }
  greet(){
    console.log(this.hi)
  }
}
let a = new People('hi')
a.greet()

类的访问权限

默认是 public，可以使用 protected，private

• public 公开类：所有人都能访问
• protected 保护类：class 内部访问，以及子类中访问
• private 私有类：仅仅 class 自己内部访问

继承

ts 使用 extends 关键字实现继承，使用 super 关键字调用父类构造函数

class Student {
  name:string
  protected sex:string
   private age:number
  constructor(name:string,age:number,sex:string){
    this.name = name
    this.age = age
    this.sex = sex
  }
}
class grade1 extends Student {
  private school: string
  constructor(name:string,age:number,sex:string,school:string){
    // 继承父类构造函数
    super(name,age,sex)
    this.school = school
  }

hi() {
  return this.sex
}
}
let p = new Student('shgopher',18,'男','一高')

抽象类

抽象类只能作为基类，不能实例化

abstract class People {
  abstract hi():void
  greet(){
    console.log("Hello")
  }
}
class students extends People {
  hi(){
    console.log("hi")
  }
}
let p = new students()
p.greet()
p.hi()