express route per typescript decorator

index.ts

import * as express from 'express';
var app = express();

app.get('/', function (req, res) {
  res.send('Hello World!');
});

app.listen(3000, function () {
  console.log('Example app listening on port 3000!');
});

export interface IQueryResult {
	data: string;
}

function RouteDecorator(app: express.Application, route: string) {
	return function (
		target: any,
		propertyKey: string,
		descriptor: TypedPropertyDescriptor<() =>Promise<IQueryResult>>) {
		console.log(`create route ${route} for method ${propertyKey}`);
		app.get(route, async (req, res) => {
			let r = await target[propertyKey]();
			res.send(r);
		});
	};
}

export class Queries {
	@RouteDecorator(app, "/a")
	bla(): Promise<IQueryResult> {
		return new Promise<IQueryResult>((resolve, reject) => {
			console.log("bla");
			resolve({ data: 'blablablablabla' });
		})
	}
}