Exploring Methods to Define Class Types as Parameter Types in Typescript

Question

Exploring Methods to Define Class Types as Parameter Types in Typescript

Is there a way to pass type information for a class, indicating to the compiler that the provided parameter is not an instance of a class but rather the definition of the class itself?

import * as Routes from '../routes';
import * as Entities from '../entities';

export class RouteManager {
  public router = Router();
  private connection = getConnectionManager().get();

  constructor() {
    this.addRoute(Routes.VideoRoute, Entities.Video);
  }

  addRoute(routeClass: AbstractRoute<AbstractEntity>, entity: AbstractEntity): void {
    const instance = new routeClass(entity, this.connection.getRepository(entity))
    this.router.get(instance.route, instance.find);
  }
}

The issue arises when trying to instantiate routeClass on the line

new routeClass(entity, this.connection.getRepository(entity))

, as the compiler interprets routeClass as an instance of

AbstractRoute<AbstractEntity>

instead of its class definition.

I attempted using

AbstractRoute<AbstractEntity>.constructor

, but it seems that Typescript is not familiar with this syntax.

typescript

Answer 1

Answer №1

The structure of this code may appear slightly unconventional at first glance. Essentially, you are defining a signature that utilizes a format such as new(...args: any[]) => T. To add more specificity, you can substitute T with your designated class and replace args with the constructor parameters.

A potential alternative approach could be:

class Bar {}
type Constructor<T> = new(...args: any[]) => T;

function generateBar(item: Constructor<Bar>) { return new item(); }

Answer 2

The structure of this code may appear slightly unconventional at first glance. Essentially, you are defining a signature that utilizes a format such as new(...args: any[]) => T. To add more specificity, you can substitute T with your designated class and replace args with the constructor parameters.

A potential alternative approach could be:

class Bar {}
type Constructor<T> = new(...args: any[]) => T;

function generateBar(item: Constructor<Bar>) { return new item(); }

Exploring Methods to Define Class Types as Parameter Types in Typescript

Answer №1

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