13、类型（Readonly）

Readonly

描述：将属性设为只读

interface Person{
    name?:string;
    age?:number;
}
let person:Readonly<Person> = {
    name:'KipSong',
  age:25
}
person.name = 'sb' // 报错Cannot assign to 'name' because it is a read-only property.

Readonly实现原理

type Readonly<T> = {
    readonly [P in keyof T]: T[P];
};