Problems with '--isolatedModules' flag and RouterContext

Question

When trying to run my deno app the following error comes out and I don't understand why .. Has anyone encountered this problem?

run command: deno run --allow-all server.ts

error:

error: TS1205 [ERROR]: Re-exporting a type when the '--isolatedModules' flag is provided requires using 'export type'.
  RouterContext,
  ~~~~~~~~~~~~~
    at file:///Users/XXXX/Documents/DenoAPP/deps.ts:4:3

deps.ts

export { Application, Router, RouterContext, Context, send } from "https://deno.land/x/[email protected]/mod.ts";
export { MongoClient } from "https://deno.land/x/[email protected]/mod.ts";
export { hashSync, compareSync} from "https://deno.land/x/[email protected]/mod.ts";
import "https://deno.land/x/[email protected]/load.ts";
export * from "https://deno.land/x/[email protected]/mod.ts";

Answer 1

See --isolatedModules for an explanation.

Checking with OAK RouterContext they do export type themselves.

So go with the flow and split

export { Application, Router, RouterContext, Context, send } from "https://deno.land/x/[email protected]/mod.ts";

into

export { Application, Router, send } from "https://deno.land/x/[email protected]/mod.ts";
export type { RouterContext, Context } from "https://deno.land/x/[email protected]/mod.ts";

Answer 2

You can use the type modifier on the type names to resolve your issue. This is the idiomatic and recommended approach for TS version ? 4.5:

export {
  Application,
  Router,
  type RouterContext,
  Context,
  send,
} from "https://deno.land/x/[email protected]/mod.ts";