Typescript vs Client Only Plugins

[north holly]

Hi,

i want to use a custom plugin only on the client side. So i could create a file like / plugins/myPlugin.client.ts.

The Plugin then should provide some Values so i can access them via const { $myPlugin } = useNuxtApp().

Is there a way to get this Typesafe?
When i use this during <script setup> it should fail, since $myPlugin is not available. But when i use it within a ClientOnly Component it should work.
But Typescript won't be happy.

Is this a valid use Case and is there a solution for this or am I doing something very stupid? 😄

[crimson pine]

Hi @north holly. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:

---

Your question is about using client-side plugins in Nuxt 3 and ensuring type safety, which is a valid use case. Let me address your concerns based on the available information.

1. Creating a client-side plugin:
   You're correct in creating a file named myPlugin.client.ts in the plugins/ directory. This naming convention ensures the plugin runs only on the client side.

2. Providing values from the plugin:
   You can indeed provide values from your plugin using the provide key. Here's an example of how you might structure your plugin:

export default defineNuxtPlugin(() => {
  return {
    provide: {
      myPlugin: () => {
        // Your plugin logic here
      }
    }
  }
})

3. Type safety:
   To ensure type safety when using your plugin, you need to declare the types for the injected properties. You can do this by augmenting the NuxtApp interface. Add the following type declaration in a .d.ts file (e.g., types/nuxt.d.ts):

declare module '#app' {
  interface NuxtApp {
    $myPlugin: () => void // Adjust the type according to your plugin's return value
  }
}

declare module 'vue' {
  interface ComponentCustomProperties {
    $myPlugin: () => void // Adjust the type according to your plugin's return value
  }
}

export {}

This type declaration will make TypeScript aware of your plugin's existence and its type.

4. Usage in <script setup> vs <ClientOnly>:
   Your observation is correct. When using the plugin in <script setup>, TypeScript might complain because it doesn't know if the code is running on the client or server. However, when used within a <ClientOnly> component, it should work without issues.

To address this, you can use type assertions or guards when accessing the plugin outside of <ClientOnly>. For example:

const nuxtApp = useNuxtApp()
if (process.client) {
  nuxtApp.$myPlugin() // TypeScript should be happy here
}

Alternatively, you can use the onMounted lifecycle hook, which only runs on the client:

import { onMounted } from 'vue'

onMounted(() => {
  const { $myPlugin } = useNuxtApp()
  $myPlugin() // This is safe and TypeScript should be happy
})

In conclusion, your approach is valid, and with proper type declarations and careful usage, you can achieve type safety with client-side plugins in Nuxt 3.

For more detailed information on plugins in Nuxt 3, you can refer to the Nuxt 3 Plugins documentation.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: