Strong strings

typingTest.ts

class ServiceModule {}

class SyncService extends ServiceModule {}
class KeycloakService extends ServiceModule {}

type ServiceModuleConstructor<T extends ServiceModule> = new() => T;

class ServiceModuleRegistry {
    private serviceTypeMap: {
        [key: string]: ServiceModuleConstructor<ServiceModule>
    } = {};

    public getServiceClass(serviceType: "sync"): ServiceModuleConstructor<SyncService>
    public getServiceClass(serviceType: "auth"): ServiceModuleConstructor<KeycloakService>
    public getServiceClass(serviceType: string): ServiceModuleConstructor<ServiceModule> {
        return this.serviceTypeMap[serviceType];
    }

    public register(type: "sync", moduleConstructor: ServiceModuleConstructor<SyncService>)
    public register(type: "auth", moduleConstructor: ServiceModuleConstructor<KeycloakService>)
    public register(type: string, moduleConstructor: ServiceModuleConstructor<ServiceModule>){
        this.serviceTypeMap[type] = moduleConstructor;
    }
}

const registry = new ServiceModuleRegistry();
registry.register("sync", SyncService);

const sync = new (registry.getServiceClass("sync"))();

console.log(sync.constructor.name); // SyncService, gets proper intellisense support