[英]How to make a generic type constraint instanciable
I have these two code fragments how can I change them so that MemberModel can be passed in as generic type and remains instanciatable so that I can extract the follow method into its own exported function? 我有这两个代码片段,如何更改它们,以便MemberModel可以作为泛型类型传递并保持可实例化,以便可以将follow方法提取到其自己的导出函数中?
export interface IFollowable {
follow(user: IUserModel): IMemberModel;
}
export class CardModel implements ICardModel, IFollowable {
public follow(user: IUserModel): IMemberModel {
let member = new MemberModel({userId: user.id});
member.role = UserRoles.follower;
this.members.push(member);
return member;
}
}
How do I make follow and IFollowable generic so that the whatever type I pass in remains newable like the MemberModel is right now? 我该如何进行关注和IFollowable泛型,以便我传递的任何类型都像MemberModel这样保持可更新状态?
so that the whatever type I pass in remains newable like the MemberModel is right now
这样我传递的任何类型都可以像MemberModel一样保持新状态
Because typescript generics are erased at compile time you need to pass them in explicitly eg using a factory as shown below: 由于打字稿泛型在编译时会被删除,因此您需要显式传递它们,例如使用如下所示的工厂:
type User = {name:string};
type Member = {name: string};
type MemberCreator = {new (user:User): Member};
interface Followable {
follow(user: User, memberCreator: MemberCreator): Member;
}
export class CardModel implements Followable {
public follow(user: User, memberCreator: MemberCreator): Member {
return new memberCreator(user);
}
}
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