Error: ERROR Cannot read properties of null (reading type)

ERROR
Cannot read properties of null (reading type’)
TypeError: Cannot read properties of null (reading type’)

<template>
  <el-card>
    <el-row :gutter="20" class="header">
      <el-col :span="7">
        <el-input placeholder="Please enter the product category name..." v-model="queryForm.query" clearable></el-input>
      </el-col>
      <el-button type="primary" :icon="Search" @click="initBigTypeList">Search</el-button>
      <el-button type="primary" :icon="DocumentAdd" @click="handleDialogValue()">Add product category</el-button>
    </el-row>
    <el-table :data="tableData" stripe style="width: 100%">
      <el-table-column prop="id" label="#ID" width="80" />
      <el-table-column prop="name" label="Product category name" width="200" />
      <el-table-column prop="image" label="Product category pictures" width="200">
        <template v-slot="scope">
          <img :src="getServerUrl() + '/image/bigType/' + scope.row.image" width="80" height="80"/>
        </template>
      </el-table-column>
      <el-table-column prop="remark" label="Product category description"/>
      <el-table-column prop="action" label="action" width="300" fixed="right">
        <template v-slot="scope">
          <el-button type="success" @click="handleImageDialogValue(scope.row)">Change image</el-button>
          <el-button type="primary" :icon="Edit" @click="handleDialogValue(scope.row.id)"/>
          <el-button type="danger" :icon="Delete" @click="handleDelete(scope.row.id)"/>
        </template>
      </el-table-column>
    </el-table>
    <el-pagination
        v-model:currentPage="queryForm.pageNum"
        v-model:page-size="queryForm.pageSize"
        :page-sizes="[10, 20, 30, 40,50]"
        layout="total, sizes, prev, pager, next, jumper"
        :total="total"
        @size-change="handleSizeChange"
        @current-change="handleCurrentChange"
    />
  </el-card>
  <Dialog v-model="dialogVisible" :dialogVisible="dialogVisible" :id="id" :dialogTitle="dialogTitle" @initBigTypeList="initBigTypeList"></Dialog>
  <ImageDialog v-model="imageDialogVisible" :imageDialogValue="imageDialogValue" @initBigTypeList="initBigTypeList"></ImageDialog>
</template>

<script setup>
import {<!-- --> Search,Delete,Edit,DocumentAdd } from '@element-plus/icons-vue'
import {<!-- --> ref } from 'vue'
import axios,{<!-- --> getServerUrl } from "@/util/axios";
import Dialog from './components/dialog'
import ImageDialog from './components/imageDialog'
import {<!-- -->ElMessage, ElMessageBox} from "element-plus";

const queryForm=ref({<!-- -->
  query:'',
  pageNum:1,
  pageSize:10
})

const total=ref(0)

const tableData = ref([])

const id=ref(-1)

const dialogTitle=ref('')

const dialogVisible=ref(false)

const imageDialogVisible=ref(false)

const imageDialogValue=ref({<!-- -->})

const initBigTypeList=async()=>{<!-- -->
  const res=await axios.post("admin/bigType/list",queryForm.value)
  tableData.value=res.data.bigTypeList;
  total.value=res.data.total;
}

initBigTypeList();

const handleSizeChange=(pageSize)=>{<!-- -->
  queryForm.value.pageNum=1;
  queryForm.value.pageSize=pageSize;
  initBigTypeList();
}

const handleCurrentChange=(pageNum)=>{<!-- -->
  queryForm.value.pageNum=pageNum;
  initBigTypeList();
}

const handleDialogValue=(bigTypeId)=>{<!-- -->
  console.log("handleDialogValue" + bigTypeId);
  if(bigTypeId){<!-- -->
    id.value=bigTypeId;
    dialogTitle.value="Modification of product categories"
  }else{<!-- -->
    id.value=-1;
    dialogTitle.value="Add product categories"
  }
  dialogVisible.value=true
}

const handleImageDialogValue=(row)=>{<!-- -->
  imageDialogVisible.value=true
  imageDialogValue.value=JSON.parse(JSON.stringify(row))
}


const handleDelete=(id,status)=>{<!-- -->
  ElMessageBox.confirm(
      'Are you sure you want to delete this record?',
      'system hint',
      {<!-- -->
        confirmButtonText: 'OK',
        cancelButtonText: 'Cancel',
        type: 'warning',
      }
  )
      .then(async() => {<!-- -->
        let res=await axios.get('admin/bigType/delete/' + id)
        if(res.data.code==0){<!-- -->
          ElMessage({<!-- -->
            type: 'success',
            message: 'Deletion successful',
          })
          initBigTypeList();
        }else{<!-- -->
          ElMessage({<!-- -->
            type: 'error',
            message: res.data.msg,
          })
        }

      })
      .catch(() => {<!-- -->

      })
}


</script>

<style lang="scss" scoped>

.header{<!-- -->
  padding-bottom: 16px;
  box-sizing: border-box;
}

.el-pagination{<!-- -->
  padding-top: 15px;
  box-sizing: border-box;
}



</style>

<template>
  <el-dialog
    :model-value="dialogVisible"
    :title="dialogTitle"
    width="30%"
  @close="handleClose"
  >

    <el-form
        ref="formRef"
        :model="form"
        :rules="rules"
        label-width="100px"
    >
      <el-form-item label="Category name" prop="name">
        <el-input v-model="form.name" />
      </el-form-item>
      <el-form-item label="Major category description" prop="remark">
        <el-input v-model="form.remark" type="textarea" :rows="4"/>
      </el-form-item>


    </el-form>
    <template #footer>
      <span class="dialog-footer">

        <el-button @click="handleClose">Cancel</el-button>
     <el-button type="primary" @click="handleConfirm">Confirm</el-button>
      </span>
    </template>
  </el-dialog>
</template>

<script setup>

import {<!-- -->defineEmits, defineProps, ref, watch} from "vue";
import axios from "@/util/axios";
import {<!-- --> ElMessage } from 'element-plus'

  const tableData=ref([])



  const props=defineProps(
      {<!-- -->
        id:{<!-- -->
          type:Number,
          default:-1,
          required: true
        },
        dialogTitle:{<!-- -->
          type:String,
          default:'',
          required: true
        },
        dialogVisible:{<!-- -->
          type:Boolean,
          default:false,
          required:true
        }
      }
  )


const form=ref({<!-- -->
  id:-1,
  name:"",
  remark:""
})

const rules=ref({<!-- -->
  name:[
    {<!-- --> required: true, message: 'Please enter the product category name'}
  ],
  remark:[
    {<!-- --> required: true, message: 'Please enter a description of the product category'}
  ]
})

const formRef=ref(null)

const initFormData=async(id)=>{<!-- -->
  const res=await axios.get("admin/bigType/" + id);
  form.value=res.data.bigType;
}



  watch(
      ()=>props.dialogVisible,
      ()=>{<!-- -->
        let id=props.id;
        if(id!=-1){<!-- -->
          initFormData(id)
        }else{<!-- -->
          formRef.value.resetFields();
          form.value={<!-- -->
            id:-1,
            name:"",
            remark:""
          }
        }
      }
  )


  const emits=defineEmits(['update:modelValue','initBigTypeList'])

  const handleClose=()=>{<!-- -->
    emits('update:modelValue',false)
  }

  const handleConfirm=()=>{<!-- -->
    formRef.value.validate(async(valid)=>{<!-- -->
      if(valid){<!-- -->

          let result=await axios.post("admin/bigType/save",form.value);
          let data=result.data;
          if(data.code==0){<!-- -->
            ElMessage.success("Execution successful!")
            formRef.value.resetFields();
            emits("initBigTypeList")
            handleClose();
          }else{<!-- -->
            ElMessage.error(data.msg);
          }


      }else{<!-- -->
        console.log("fail")
      }
    })
  }

</script>

<style scoped>

</style>

After correction: The unit found the reason