3-ts接口和对象类型

 

interface A {
  name: string
}

interface A {
  age: number
}
//声明两个对象最后会合并，

let obj:A = {
  name: 'tom',
  age: 12
}

console.log(obj)

interface Person {
  name: string,
  age?:number, //?表示对象中age可有可没有
  [propName: string]: any, //表示对象中可以有未知对象
  readonly param: string, //只读属性不可以修改
  fn(): number, //定义一个函数
}

let p:Person = {
  name:'张三',
  abc: 'test',
  param: 'param',
  fn:():number => {
    return 123
  }
}
p.name = '李四'
console.log(p)


interface A {
  name: string
}

interface B extends A {
  age: number
}

let po:B = {
  name: 'tom',
  age: 9899
}

console.log(po)