生命周期鈎子函數
vue3 更新了生命周期鈎子函數。
可以直接通過 import 對應的函數(例如:onMounted)來注冊生命周期鈎子函數。
Options API -> Hook inside setup
beforeCreate-> use setup()created-> use setup()- beforeMount -> onBeforeMount
- mounted -> onMounted
- beforeUpdate -> onBeforeUpdate
- updated -> onUpdated
- beforeUnmount -> onBeforeUnmount
- unmounted -> onUnmounted
- errorCaptured -> onErrorCaptured
- renderTracked -> onRenderTracked(調試用)
- renderTriggered -> onRenderTriggered(調試用)
因為 setup 是在 beforeCreated 和 created 幾乎是同時進行的,所以可以將在這兩個生命周期里的代碼寫在 setup 里面。

使用:
import { onMounted, onUpdated, onUnmounted } from 'vue'
const MyComponent = {
setup() {
onMounted(() => {
console.log('mounted!')
})
onUpdated(() => {
console.log('updated!')
})
onUnmounted(() => {
console.log('unmounted!')
})
}
}