ts_typetype将多个采用相同类型约束的变量复用为同类。 type也可以约束对象类型父子type的继承相同ty

type将相同类型约束复用。

let phone:number|string
let age:number|string

// type 
type StrOrNum = number|string
let phone:StrOrNum
let age:StrOrNum

type也可以约束对象类型

type obj = {name:string}
let ws:obj = {name:'ws'}

type不能重复定义 => 不能同类扩展 => 扩展需要另创type

type game = {
    type:string
}
type game = {
   class:string
}

type继承

type animal = {
    class:string
}
// type brid = animal
type brid = animal & {
    canFly:boolean
}

let luoluo:brid = {
    class:'鸟类',
    canFly:true
}