1.vue2.x生命周期:

2.vue3.0生命周期：

• Vue3.0中可以继续使用Vue2.x中的生命周期钩子，但有两个被更名：

1. beforeDestroy改名为beforeUnmount

2. destroyed改名为unmounted

• Vue3.0也提供了Composition API 形式的生命周期钩子,与Vue2.x中钩子对应关系如下:

1. beforeCreate ==>setup()

2. created ==>setup()

3. beforeMount ==>onBeforeMount

4. mounted ==>onMounted

5. beforeUpdate ==>onBeforeUpdated

6. updated ==>onUpdated

7. beforeUnmount ==>onBeforeUnMount

8. unmounted ==>onUnMounted