Why doesn"t RT:obj.list & & obj.list.length first determine whether obj.list has a value and then report that length is undefined?
so I always deal with it this way (I can probably understand why, but I don"t know the professional explanation)
{
orderMsgJson0.list && orderMsgJson0.list.length ? [
orderMsgJson0.list.map(item => (
<p dangerouslySetInnerHTML={{ __html: formatNullStr(this.strReplace(item.senderMsg, `scm.html?tab=saleOrderDetail&orderId=${item.orderId}`)) }}>
)),
<p className="person-more"><a href="-sharp">>></a>
] :
}