是否可以在公共对象中添加私钥?
export class user {
public details: {
lastname: string,
firstname: string,
username: string
}
}
我希望不能在类的方法外部设置用户名。例如,类似这样的东西:
export class user {
public details: {
lastname: string,
firstname: string,
private _username: string
}
public setUsername() {
this.details._username = `${lastname} ${firstname}`;
}
}
为什么不只是
export class user {
public lastname: string,
public firstname: string,
private _username: string
public setUsername() {
this._username = `${this.lastname} ${this.firstname}`;
}
}
我不确定为什么要这么做(并且如果您确实想要类似private
的行为,而不是readonly
),但是在这种情况下,我建议您将类放入模块中仅导出预期的面向公众的类型。类似于以下内容:
namespace Library {
export interface Details {
lastname: string;
firstname: string;
}
interface PrivateDetails extends Details {
username: string;
}
class PrivateUser {
details: PrivateDetails;
constructor(lastname: string, firstname: string) {
this.details = { lastname, firstname, username: "" };
this.setUsername(); // I guess?
}
setUsername() {
this.details.username = `${this.details.lastname} ${
this.details.firstname
}`;
}
}
export type User = Omit<PrivateUser, "details"> & {
details: Details;
};
export const User: new (
...args: ConstructorParameters<typeof PrivateUser>
) => User = PrivateUser;
}
因此库中有一个PrivateUser
类和PrivateDetails
类型,其中details
的PrivateUser
属性是PrivateDetails
。这些类型和值不会导出。我们导出的是User
类*和Details
类型,其中details
的User
属性是Details
。 (*请注意,我们实际上正在导出type
和const
,它们都命名为User
。type
对应于User
实例的类型,const
是构造函数。class
]定义会自动执行此操作,但是我们必须在此处两行执行。]
好的,让我们使用它:
import User = Library.User;
const u = new User("Turing", "Alan");
console.log(u.details.firstname); // Turing
console.log(u.details.lastname); // Alan
console.log(u.details.username); // error!
// Property 'username' does not exist on type 'Details'.
// of course, at runtime, it still outputs "Turing Alan", just like a private property does
u.details.lastname = "Alda";
u.setUsername(); // okay
console.log(u.details.username); // still compiler error, outputs "Alda Alan" at runtime
我以您想要的方式运作。从内部Library
,PrivateUser
类可以完全访问其details.username
属性。但是从外部来看,暴露的User
类则没有。这意味着如果您尝试使用它将出现编译器错误。当然,在运行时访问将成功,但是private
属性也将以这种方式工作,所以我认为可以。
好的,希望能有所帮助;祝你好运!