element table Error in callback for watcher “data“: “TypeError: Cannot read properties of null (read

element table Error in callback for watcher “data”: “TypeError: Cannot read properties of null (reading ‘reduce’)”

problem

On the list page, the front-end and back-end joint debugging interface found that the console reported
an error Error in callback for watcher “data”: “TypeError: Cannot read properties of null (reading 'reduce')”

reason

From the prompt, it should be caused by the element table traversing the list data.
Reason 1: The list initialization data is null.
Reason 2: The backend interface returns null and is not processed.

solution

Option 1: Change the list initialization to []
Option 2: Adjust the background interface. When there is no data, return to []

// 方案1 
data:{
    
    
    list: [], // null 改为 []
}

// 方案2  接口数据调整 
// 如果接口不能改，只能自己处理
listOrder(bodydata).then(response => {
    
        
    // this.list = response.data.data.list // before     
    this.list = response.data.data.list || [] // after 
}