TypeError: Cannot read properties of undefined (reading '$pinia')

[liyuan1125]

main.ts

import { createApp } from 'vue'
import App from './App.vue'
import { createPinia } from 'pinia'
const store = createPinia()
const app = createApp(App)
app.use(store)
app.mount('#app')

store.ts

import { defineStore } from 'pinia'
import { User } from '@/types/user.ts'

type AppStoreState = {
  users: User[]
}

type AppStoreGetter = {}

type AppStoreAction = {
  fetchUsers(): void
}

export const useAppStore = defineStore<
  'app',
  AppStoreState,
  AppStoreGetter,
  AppStoreAction
>({
  id: 'app',
  state: () => ({
    users: []
  }),

  actions: {
    fetchUsers() {
// TODO
 },
  },
})

App.vue

<script setup lang="ts">
  import { onMounted } from 'vue'
  import { useAppStore } from '.store.ts'
  import { mapActions } from 'pinia'

  const { fetchUsers } = mapActions(useAppStore, {
    fetchUsers: 'fetchUsers',
  })

  
  onMounted(() => {
    fetchUsers()
  })
</script>
<template>
<-- TODO -->
</template>

[posva]

mapActions() are for options API. Check https://pinia.vuejs.org/core-concepts/#using-the-store, you just need to call useAppStore() instead.

BTW don't pass the generics to defineStore(), pinia infers the types for you 😉