typescript 入门-接口

interface 定义

interface i_Tree{
  leftLeaf: string
  rightLeaf: string
}
// 作为类型定义
const tree: i_Tree = {
  leftLeaf: 'left',
  rightLeaf: 'right'
}

可选属性

interface Man{
   name: string // 必选
   job?: string // 可选
}

只读

interface Man{
  readonly sex:string
  name: string
  job?: string
}

函数描述

interface i_talk{
  (msg:string): void;
}
const talk:i_talk = (msg: string) => {
  console.log(msg)
}

可索引

interface i_list{
  [index: number]: string
}
const li: i_list = ['ni', 'mi']

类描述

interface i_Man{
  name: string
}


class Man implements i_Man{
  name:string
  constructor(name: string) {
    this.name = name
  }
}




const c = new Man('cc')
console.log(c.name)

类构造器描述

interface i_Man{
  name: string
}


class Man implements i_Man{
  name:string
  constructor(name: string) {
    this.name = name
  }
}


// 定义构造函数接口
interface i_ManConstructor{
  new (name:string): i_Man
}


// 接收类定义作为参数
function createMan(c: i_ManConstructor, name: string):i_Man{
  return new c(name)
}

混合类型

interface i_talk{
  (msg?: string): void
  defaultMsg?: string
}




const talk: i_talk = function (msg?: string): void{
  console.log(msg || talk.defaultMsg)
}




talk.defaultMsg = 'not find msg'
talk()
// 函数也是对象，可以拥有自己的属性

继承接口

interface i_A{
  propA: string
}


interface i_B{
  propB: string
}


interface i_C extends i_A, i_B{
  propC: string
}


const c: i_C = {
  propA: 'a',
  propB: 'b',
  propC: 'c',
} 

继承类

class Control {
    private state: any;
}


interface SelectableControl extends Control {
    select(): void;
}


class Button extends Control implements SelectableControl {
    select() { }
}


class TextBox extends Control {
    select() { }
}


// 错误：“Image”类型缺少“state”属性。
class Image implements SelectableControl {
    select() { }
}


class Location {}