Typescript Import Problem after updating Deno

Question

I recently update deno from v1.3.0 to v1.4.0. Before updating, my code doesn't have any problem, but after that i have this error:

error: TS1205 [ERROR]: Re-exporting a type when the '--isolatedModules' flag is provided requires using 'export type'.
  LevelName,
  ~~~~~~~~~
    at https://deno.land/x/[email protected]/deps.ts:8:3

TS1205 [ERROR]: Re-exporting a type when the '--isolatedModules' flag is provided requires using 'export type'.
export { LogConfig, setup, prefix } from "./branch.ts";
         ~~~~~~~~~
    at https://deno.land/x/[email protected]/mod.ts:3:10

TS1371 [ERROR]: This import is never used as a value and must use 'import type' because the 'importsNotUsedAsValues' is set to 'error'.
import { WatcherConfig } from "./watcher.ts";
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    at https://deno.land/x/[email protected]/src/config.ts:14:1

TS1371 [ERROR]: This import is never used as a value and must use 'import type' because the 'importsNotUsedAsValues' is set to 'error'.
import { RunnerConfig } from "./runner.ts";
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    at https://deno.land/x/[email protected]/src/config.ts:15:1

TS1371 [ERROR]: This import is never used as a value and must use 'import type' because the 'importsNotUsedAsValues' is set to 'error'.
import { Args } from "./args.ts";
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    at https://deno.land/x/[email protected]/src/config.ts:18:1

TS1371 [ERROR]: This import is never used as a value and must use 'import type' because the 'importsNotUsedAsValues' is set to 'error'.
import { Template } from "./templates.ts";
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    at https://deno.land/x/[email protected]/src/config.ts:19:1

TS1371 [ERROR]: This import is never used as a value and must use 'import type' because the 'importsNotUsedAsValues' is set to 'error'.
import { Denon, DenonEvent } from "../denon.ts";
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    at https://deno.land/x/[email protected]/src/daemon.ts:5:1

TS1371 [ERROR]: This import is never used as a value and must use 'import type' because the 'importsNotUsedAsValues' is set to 'error'.
import { CompleteDenonConfig } from "./config.ts";
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    at https://deno.land/x/[email protected]/src/daemon.ts:6:1

TS1371 [ERROR]: This import is never used as a value and must use 'import type' because the 'importsNotUsedAsValues' is set to 'error'.
import { ScriptOptions } from "./scripts.ts";
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    at https://deno.land/x/[email protected]/src/daemon.ts:7:1

I found a page that fix this problem, but this error looks like it's coming from third party library. I also use Denon to run the script. Here is my imported package:

import { Application } from "https://deno.land/x/oak/mod.ts";
import { oakCors } from "https://deno.land/x/cors/mod.ts";
import { Router } from "https://deno.land/x/oak/mod.ts";
import { RouterContext } from "https://deno.land/x/oak/mod.ts";
import * as bcrypt from "https://deno.land/x/bcrypt/mod.ts";
import { SmtpClient } from "https://deno.land/x/smtp/mod.ts";
import { MongoClient } from "https://deno.land/x/[email protected]/mod.ts";

And this is my denon.json:

{
  "$schema": "https://deno.land/x/denon/schema.json",
  "scripts": {
    "start": {
      "cmd": "deno run --unstable server.ts",
      "allow": [
        "net",
        "write",
        "read",
        "plugin"
      ]
    }
  }
}

Is there a way to fix this? or a way to downgrade Deno?

Answer 1

There was an unstable feature added in Deno v1.4.0. https://github.com/denoland/deno/pull/7413. A similar issue was here https://github.com/Jozty/Fae/issues/32 This will be fixed by the library writers or you can raise PR with a fix. A temporary fix is to downgrade Deno to v1.3.0