Memahami Kereaktifan Vue dengan Pinia Stores

Di tempat kerja saya, saya ditugaskan untuk mencipta kedai sembang olok-olok untuk kerja pembangun tempatan dalaman, dan semasa berbuat demikian saya membuat sedikit nota tentang Vue (saya mempunyai sedikit pengalaman, tetapi tidak dengan cangkuk), Jadi ini hanyalah nota obsidian saya, saya harap ia berguna untuk anda :)

Jadual Kandungan

1. Rujukan dan Rujukan Reaktif
2. Tonton dan Kereaktifan
3. Integrasi Kedai Pinia
4. Contoh Praktikal
5. Amalan Terbaik
6. Gotcha Biasa

Rujukan dan Rujukan Reaktif

Apa itu Ref?

ref ialah cara Vue menjadikan nilai primitif reaktif. Ia membungkus nilai dalam objek reaktif dengan sifat .value.

import { ref } from 'vue'

// Inside Pinia Store
export const useMyStore = defineStore('my-store', () => {
  // Creates a reactive reference
  const count = ref<number>(0)

  // To access or modify:
  function increment() {
    count.value++  // Need .value for refs
  }

  return {
    count,  // When exposed, components can use it without .value
    increment
  }
})

Jenis Rujukan di Kedai

// Simple ref
const isLoading = ref<boolean>(false)

// Array ref
const messages = ref<Message[]>([])

// Complex object ref
const currentUser = ref<User | null>(null)

// Ref with undefined
const selectedId = ref<string | undefined>(undefined)

Tonton dan Kereaktifan

Penggunaan Jam Tangan Asas

import { watch, ref } from 'vue'

export const useMyStore = defineStore('my-store', () => {
  const messages = ref<Message[]>([])

  // Simple watch
  watch(messages, (newMessages, oldMessages) => {
    console.log('Messages changed:', newMessages)
  })
})

Pilihan Tontonan

// Immediate execution
watch(messages, (newMessages) => {
  // This runs immediately and on changes
}, { immediate: true })

// Deep watching
watch(messages, (newMessages) => {
  // Detects deep object changes
}, { deep: true })

// Multiple sources
watch(
  [messages, selectedId], 
  ([newMessages, newId], [oldMessages, oldId]) => {
    // Triggers when either changes
  }
)

Integrasi Kedai Pinia

Struktur Stor dengan Ruj

export const useMyStore = defineStore('my-store', () => {
  // State
  const items = ref<Item[]>([])
  const isLoading = ref(false)
  const error = ref<Error | null>(null)

  // Computed
  const itemCount = computed(() => items.value.length)

  // Actions
  const fetchItems = async () => {
    isLoading.value = true
    try {
      items.value = await api.getItems()
    } catch (e) {
      error.value = e as Error
    } finally {
      isLoading.value = false
    }
  }

  return {
    items,
    isLoading,
    error,
    itemCount,
    fetchItems
  }
})

Kedai Mengarang

export const useMainStore = defineStore('main-store', () => {
  // Using another store
  const otherStore = useOtherStore()

  // Watching other store's state
  watch(
    () => otherStore.someState,
    (newValue) => {
      // React to other store's changes
    }
  )
})

Contoh Praktikal

Autorefresh Pelaksanaan

export const useChatStore = defineStore('chat-store', () => {
  const messages = ref<Message[]>([])
  const refreshInterval = ref<number | null>(null)
  const isRefreshing = ref(false)

  // Watch for auto-refresh state
  watch(isRefreshing, (shouldRefresh) => {
    if (shouldRefresh) {
      startAutoRefresh()
    } else {
      stopAutoRefresh()
    }
  })

  const startAutoRefresh = () => {
    refreshInterval.value = window.setInterval(() => {
      fetchNewMessages()
    }, 5000)
  }

  const stopAutoRefresh = () => {
    if (refreshInterval.value) {
      clearInterval(refreshInterval.value)
      refreshInterval.value = null
    }
  }

  return {
    messages,
    isRefreshing,
    startAutoRefresh,
    stopAutoRefresh
  }
})

Memuatkan Pengurusan Negeri

export const useDataStore = defineStore('data-store', () => {
  const data = ref<Data[]>([])
  const isLoading = ref(false)
  const error = ref<Error | null>(null)

  // Watch loading state for side effects
  watch(isLoading, (loading) => {
    if (loading) {
      // Show loading indicator
    } else {
      // Hide loading indicator
    }
  })

  // Watch for errors
  watch(error, (newError) => {
    if (newError) {
      // Handle error (show notification, etc.)
    }
  })
})

Amalan Terbaik

1. Ref Permulaan

// ❌ Bad
const data = ref()  // Type is 'any'

// ✅ Good
const data = ref<string[]>([])  // Explicitly typed

2. Pembersihan Tontonan

// ❌ Bad - No cleanup
watch(source, () => {
  const timer = setInterval(() => {}, 1000)
})

// ✅ Good - With cleanup
watch(source, () => {
  const timer = setInterval(() => {}, 1000)
  return () => clearInterval(timer)  // Cleanup function
})

3. Dikira lwn Watch

// ❌ Bad - Using watch for derived state
watch(items, (newItems) => {
  itemCount.value = newItems.length
})

// ✅ Good - Using computed for derived state
const itemCount = computed(() => items.value.length)

4. Organisasi Stor

// ✅ Good store organization
export const useStore = defineStore('store', () => {
  // State refs
  const data = ref<Data[]>([])
  const isLoading = ref(false)

  // Computed properties
  const isEmpty = computed(() => data.value.length === 0)

  // Watchers
  watch(data, () => {
    // Handle data changes
  })

  // Actions
  const fetchData = async () => {
    // Implementation
  }

  // Return public interface
  return {
    data,
    isLoading,
    isEmpty,
    fetchData
  }
})

Gotcha biasa

1. Melupakan .nilai

// ❌ Bad
const count = ref(0)
count++ // Won't work

// ✅ Good
count.value++

1. Masa Tonton

// ❌ Bad - Might miss initial state
watch(source, () => {})

// ✅ Good - Catches initial state
watch(source, () => {}, { immediate: true })

1. Memori Bocor

// ❌ Bad - No cleanup
const store = useStore()
setInterval(() => {
  store.refresh()
}, 1000)

// ✅ Good - With cleanup
const intervalId = setInterval(() => {
  store.refresh()
}, 1000)
onBeforeUnmount(() => clearInterval(intervalId))

Ingat: Sentiasa pertimbangkan pembersihan, keselamatan jenis dan penyusunan yang betul apabila bekerja dengan rujukan dan jam tangan di kedai Pinia

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