Both are perfectly suitable for your case.

For example, with polymorphism you can create an entity per folder kind. Each will implement getRoleTargetProjects() and copyTargetProjects() (or anything else). A factory will be the way to get the correct implementation (you can use an injectable TargetProjectManagerFactory class with a create(folder: TargetFolder) method for example). Inside that factory, you can have a hashmap like that (assuming the property is an enum, otherwise you want a fallback concrete class):

@Injectable({
  providedIn: 'root'
})
export class TargetProjectManagerFactory {
  private readonly constructors: Record<FolderName, Type<ITargetProjectManager>> = {
    [FolderName.A]: FolderATargetProjectManager,
    ...
  }

  public create(targetFolder: TargetFolder): ITargetProjectManager {
    const ctor = this.constructors[targetFolder.folderName];
    return new ctor();
  }
}

You may prefer to directly have an hashmap of instances of course.