一、生命周期
vu3在组合式API（Composition API）中使用生命周期钩子时需要先引入，vue2在选项API（Options API）中可以直接调用生命周期钩子
//vue3 <script setup> import { onMounted } from 'vue' onMounted(()=>{ //逻辑1 }) onMounted(()=>{ //逻辑2，可将不同的逻辑拆分到多个onMounted，依然按顺序执行，不会被覆盖 }) </script> //vue2 <script> export default { mounted(){ //直接调用生命周期钩子，逻辑写在一起 } } </script>
常用生命周期对比如下：
| vue2 | vue3 |
| beforeCreate | |
| created | |
| beforeMount | onBeforeMount |
| mounted | onMounted |
| beforeUpdate | onBeforeUpdate |
| updated | onUpdated |
| beforeDestroy | onBeforeUnmount |
| destroyed | onUnmounted |