Why do I report an error when I set _ expanded to true in the data bound to the table component of iview

Why does setting _ expanded to true in the data I bind to the table component of iview report an error
let tempData = response.data.data;

    for (let i = 0; i < tempData.length; iPP) {
      tempData[i].date = tempData[i].list[0].borrow_date.substring(0, 7);
      tempData[i]._expanded = true;
    }
    _this.data1 = tempData;
    

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Mar.05,2021

_ this.data1 = tempData.map (item= > {

)
    item._expanded=true;return item;
})
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1e471b9-43f61.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e471b9-43f61.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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