create_route.ts

import t from 'io-ts';
import { Request } from 'hapi';
import { PathReporter } from 'io-ts/lib/PathReporter';
import { isLeft } from 'fp-ts/lib/Either';

interface Params {
  path?: t.HasProps;
  query?: t.HasProps;
  body?: t.Any;
}

interface Route {
  path: string;
  method: 'GET' | 'POST' | 'PUT' | 'DELETE';
  params: Params;
  handler: (request: Request) => {};
}

export const createRoute = (route: Route) => {
  const { params, handler, ...rest } = route;

  return {
    ...rest,
    handler: (request: Request) => {
      const requestData = {
        body: request.payload,
        path: request.params,
        query: request.query
      };

      (Object.keys(params) as Array<keyof Params>).forEach(key => {
        const codec = params[key] as t.Any;
        const result = codec.decode(requestData[key]);
        if (isLeft(result)) {
          throw new Error(PathReporter.report(result).join('\n'));
        }
      });

      return handler(request);
    }
  };
};