npm install typescript -g

 function jspang(){
    let web: string="Hello World"
    console.log(web)
 }

 jspang()

npm install -g ts-node

ts-node Demo1.ts

count : number = 1;

interface XiaoJieJie {
    uname: string,
    age: number
}

const xiaohong :XiaoJieJie = {
    uname: '小红',
    age: 18
}
console.log(xiaohong.age)