//初始化项目
npm init

//安装typescript
npm install  typescript

//创建一个typescript文件 test.ts
//编译test.ts文件
tsc test.ts

//class代码范例

class Person{
  protected name: String;
  constructor(name:string){
      this.name=name;
  }
  greet(){
    return `${this.name}向你问好`;
  }
}
class Student extends Person{
  private major:string;

  constructor(name:string,major:string){
    super(name);
    this.major=major;
  }
  studentGreet(){
    return  `${this.major}系的${this.name}向你问好`;
  }
}
let xiaoming=new Student('小明','哲学');
console.log(xiaoming.studentGreet());