TS7016: Could not find a declaration file for module '@hotwired/turbo-rails'

[szTheory]

Ran into this error while upgrading a Rails 6 app that uses TypeScript and Turbolinks to the new Turbo. Any ideas? No results on DefinitelyTyped yet.

ERROR in app/javascript/packs/application.ts:10:30
TS7016: Could not find a declaration file for module '@hotwired/turbo-rails'. '/myapp/node_modules/@hotwired/turbo-rails/app/assets/javascripts/turbo.js' implicitly has an 'any' type.
Try `npm i --save-dev @types/hotwired__turbo-rails` if it exists or add a new declaration (.d.ts) file containing `declare module '@hotwired/turbo-rails';`
  8 | 
> 9 | import { Turbo, cable } from "@hotwired/turbo-rails";

[javan]

Can you share a sample app or your relevant TypeScript configuration? I can't reproduce in a stock setup on Rails 6.1:

$ rails new wired && \
  cd wired && \
  bin/rails webpacker:install:typescript && \
  yarn add @hotwired/turbo-rails && \
  rm -rf app/javascript/packs/* && \
  echo "import { Turbo, cable } from \"@hotwired/turbo-rails\"" > app/javascript/packs/application.ts && \
  echo "console.log({ Turbo, cable })" >> app/javascript/packs/application.ts && \
  bin/webpack

…

js/application-d58c957e0d7290104479.js.map    204 KiB  application  [emitted] [dev]        application
                             manifest.json  364 bytes               [emitted]              
Entrypoint application = js/application-d58c957e0d7290104479.js js/application-d58c957e0d7290104479.js.map
[./app/javascript/packs/application.ts] 102 bytes {application} [built]

[szTheory]

Thanks javan. If you add "strict": true to tsconfig.json then run tsc it produces the error. It looks like webpacker transpiles the TypeScript to JS but doesn't run the type checker itself.

[javan]

I see. So this is more of a feature request to add TypeScript declarations than an issue since you'd encounter the same problem trying to use any library published without types. Noted! In the meantime, you may find some of these workarounds helpful.

[szTheory]

Well it used to work in Turbolinks 6 so this is new behavior after upgrading by following the install instructions in the readme but I see your point. Regardless of how you classify it I'm sure a lot of TypeScript users would appreciate type definitions on the interface to help migrate to the new version. Thanks again for looking into this.

[javan]

We do have definitions for Turbo itself, which is written in TypeScript, and passes right through this package:

turbo-rails/app/javascript/turbo/index.js

Line 2 in 6df29f7

export * as Turbo from "@hotwired/turbo"

It would be pretty straightforward to re-export its types too along with a few manual definitions for:

turbo-rails/app/javascript/turbo/cable.js

Lines 3 to 16 in 6df29f7

	export async function getConsumer() {
	if (consumer) return consumer
	const { createConsumer } = await import("@rails/actioncable/src")
	return setConsumer(createConsumer())
	}
	export function setConsumer(newConsumer) {
	return consumer = newConsumer
	}
	export async function subscribeTo(channel, mixin) {
	const { subscriptions } = await getConsumer()
	return subscriptions.create(channel, mixin)
	}

Happy to accept a PR if anyone feels like taking that on!

[Jonnykoder]

Has anyone solved this issue? I'm having the similar problem on rails 7.

[mockdeep]

Depending on how deeply you're using Turbo, you can define your own types for your specific use cases. In our case, for the moment, we only disabling Drive, so this worked for us:

// app/javascript/@types/turbo.d.ts
declare module '@hotwired/turbo-rails' {
  type TurboSession = {
    drive: boolean;
  }

  type Turbo = {
    session: TurboSession;
  }

  export const Turbo: Turbo;
}

[ReazerDev]

Hi, wouldn't it be possible to just release the typings in the npm package?
This should fix this issue :)

[kzkn]

I have opened two pullreqs to resolve this issue:

• Convert JavaScript To TypeScript #392
• [hotwired__turbo-rails] Create types for @hotwired/turbo-rails DefinitelyTyped/DefinitelyTyped#62834 (closed once)

In order to keep up with turbo updates, I thought it would be preferable to convert turbo-rails to TypeScript as well.
If it is too much to convert turbo-rails to TypeScript, I think it would be better to follow the TypeScript community's practice and publish the type information from DT.

What do you think?

If there is a lightweight way to re-export just the type information from turbo-rails without converting to TypeScript, that would be fine too.

[paulorivera27]

+1 on this one..

[kzkn]

I've opened #392 about ten months ago. Please upvote 😄

[brunoprietog]

Turbo left TypeScript. Closing this