I am trying to initalize a project with Vue3 and typescript, but after adding vuex to the project, it won´t compile.

What I did:

1. First I created the project with create-vue, using the recommend options:

Creating Vue Project

2. Installed vuex:

npm install vuex@next --save

3. Followed the steps in Vuex Docs: Typescript support

So, in my simple store file I have:

import { type InjectionKey } from 'vue'
import { createStore, Store } from 'vuex'

// define your typings for the store state
export interface State {
  count: number
}

// define injection key
export const key: InjectionKey<Store<State>> = Symbol()

export const store = createStore<State>({
  state: {
    count: 0
  }
})

But if I run npm run build, this is the result:

src/stores/index.ts:2:36 - error TS7016: Could not find a declaration file for module 'vuex'. '/home/user/projects/vue_projects/init-test/node_modules/vuex/dist/vuex.mjs' implicitly has an 'any' type.
  There are types at '/home/user/projects/vue_projects/init-test/node_modules/vuex/types/index.d.ts', but this result could not be resolved when respecting package.json "exports". The 'vuex' library may need to update its package.json or typings.

2 import { createStore, Store } from 'vuex'

It seems that it has found vuex types, but could not import anyway. How do I solve that?

I already added a vuex.d.ts, following the vuex docs.

import { Store } from 'vuex'

declare module '@vue/runtime-core' {
  // declare your own store states
  interface State {
    count: number
  }

  // provide typings for `this.$store`
  interface ComponentCustomProperties {
    $store: Store<State>
  }
}

It appears to be caused by a change in a relatively new version of typescript that no longer recognizes vuex type definitions.

Workaround 1

Save the following code under an appropriate directory with a name like vuex.d.ts. This should allow TypeScript to correctly recognize the vuex module.

declare module "vuex" {
  export * from "vuex/types/index.d.ts";
  export * from "vuex/types/helpers.d.ts";
  export * from "vuex/types/logger.d.ts";
  export * from "vuex/types/vue.d.ts";
}

Workaround 2

I have not confirmed this, but using a slightly older version of typescript may solve the problem.