Vue.js 3 and typescript : Property '$store' does not exist on type 'ComponentPublicInstance

Can't find anything to solve this seemingly obvious issue.

Just upgraded from Vue 2 to Vue 3 and Vuex with Typescript.

this.$store doesn't seem to be accessible, despite following the Vue 3 instructions.

ERROR in src/components/FlashMessages.vue:28:25 TS2339: Property '$store' does not exist on type 'ComponentPublicInstance<{}, {}, {}, { getAllFlashMessages(): Word; }, {}, EmitsOptions, {}, {}, false, ComponentOptionsBase<{}, {}, {}, { getAllFlashMessages(): Word; }, {}, ComponentOptionsMixin, ComponentOptionsMixin, EmitsOptions, string, {}>>'.

    26 |     computed: {
    27 |         getAllFlashMessages (): FlashType {
  > 28 |             return this.$store.getters.getFlashMessages;
       |                         ^^^^^^
    29 |         },
    30 |     },
    31 | 

main.ts

import { createApp } from 'vue'
import App from './App.vue'
import './registerServiceWorker'
import router from './router'
import store from './store'
import './assets/styles/index.css'

const app = createApp(App)

app.use(store)
app.use(router)
app.mount('#app')

store.ts

import { createStore } from 'vuex'
import FlashType from '@/init'

export default createStore({
    state: {
        flashMessages: [] as FlashType[],
    },

    getters: {
        getFlashMessages (state) {
            return state.flashMessages
        }
    },

FlashMessages.vue

<script lang="ts">
import { defineComponent } from "vue";
import FlashType from "@/init";

export default defineComponent({
    name: "FlashMessages",

    data () {
        return {};
    },

    computed: {
        getAllFlashMessages (): FlashType {
            return this.$store.getters.getFlashMessages;
        },
    },

init.ts

export type FlashType = {
    kind: 'success' | 'error';
    message: string;
    time: number;
}

Any wisdom appreciated :)

File structure

├── .editorconfig
├── client
│   ├── babel.config.js
│   ├── CONTRACTS.md
│   ├── cypress.json
│   ├── jest.config.js
│   ├── package.json
│   ├── package-lock.json
│   ├── postcss.config.js
│   ├── public
│   │   ├── favicon.ico
│   │   ├── index.html
│   │   └── robots.txt
│   ├── README.md
│   ├── src
│   │   ├── App.vue
│   │   ├── assets
│   │   │   ├── logo.png
│   │   │   └── styles
│   │   │       └── index.css
│   │   ├── components
│   │   │   ├── admin
│   │   │   │   ├── AdminAdd.vue
│   │   │   │   ├── AdminList.vue
│   │   │   │   ├── AdminWord.vue
│   │   │   │   ├── EmotionAdd.vue
│   │   │   │   ├── EmotionsList.vue
│   │   │   │   └── Emotion.vue
│   │   │   └── FlashMessages.vue
│   │   ├── init.ts
│   │   ├── main.ts
│   │   ├── registerServiceWorker.ts
│   │   ├── router
│   │   │   └── index.ts
│   │   ├── shims-vue.d.ts
│   │   ├── store
│   │   │   └── index.ts
│   │   └── views
│   │       ├── About.vue
│   │       ├── Admin.vue
│   │       ├── Emotions.vue
│   │       └── Home.vue
│   ├── tsconfig.json
│   └── vue.config.js
├
└── server
    ├── api
    ├── api.bundle.js
    ├── index.ts
    ├── logger
    │   └── logger.ts
    ├── models
    ├── nodemon.json
    ├── package.json
    ├── package-lock.json
    ├── router
    │   ├── db.ts
    │   └── emotions.ts
    ├── tsconfig.json
    └── webpack.config.js

This is my first time properly using eslint, so I'm not sure if I've set it up correctly.. I ended up with a different tsconfig in /client and /server directories.

client/tsconfig.json

{
  "compilerOptions": {
    "target": "esnext",
    "module": "esnext",
    "strict": true,
    "jsx": "preserve",
    "importHelpers": true,
    "moduleResolution": "node",
    "skipLibCheck": true,
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "sourceMap": true,
    "baseUrl": "./",
    "types": [
      "webpack-env",
      "jest"
    ],
    "paths": {
      "@/*": [
        "src/*"
      ]
    },
    "lib": [
      "esnext",
      "dom",
      "dom.iterable",
      "scripthost"
    ]
  },
  "include": [
    "src/**/*.ts",
    "src/**/*.tsx",
    "src/**/*.vue",
    "tests/**/*.ts",
    "tests/**/*.tsx"
  ],
  "exclude": [
    "node_modules"
  ]
}

Next to shims-vue.d.ts file create another file called shims-vuex.d.ts with the following content :

import { Store } from '@/store';// path to store file

declare module '@vue/runtime-core' {
  interface ComponentCustomProperties {
    $store: Store;
  }
}

For more check the Typescript support section for more details

I had a similar error but in VS Code. As of Vuex 4, this is the preferred method:

// vuex-shim.d.ts

import { ComponentCustomProperties } from 'vue'
import { Store } from 'vuex'

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

  interface ComponentCustomProperties {
    $store: Store<State>
  }
}

Docs: https://next.vuex.vuejs.org/guide/migrating-to-4-0-from-3-x.html#typescript-support

And I had to disable then enable Vetur again.

Try adding

app.provide("$store", store);

in your main.ts file before mounting. This method works on my side and the final code looks like

...
let app = createApp(App);
app.provide("$store", store);
app.use(store);
app.mount("#app");