[] in reactive() is null? #2882
Description
Version
3.0.4
Reproduction link
https://gitee.com/liguangzheng777/school/blob/master/src/views/student/add.vue
Steps to reproduce
<!-- html -->
<el-option v-for="(item, i) in state.classesArr" :key="i" :label="item.name" :value="item.name"> </el-option>
// js
const state = reactive({classesArr: []})
onBeforeMount(() => {
state.classesArr = [0,1,2]
})
console:
Uncaught (in promise) TypeError: oldChildren is null
if : const state = reactive({classesArr: [0]})
code run success
What is expected?
lgz
What is actually happening?
[] is null?? how to solve
how to solve,thanks