ts中类型为 "string" 的表达式不能用于索引类型 "{}

const handerField = (item: number) => {
   caselist= data.showList[item]//报错
}

解决方法：

const handerField = (item: number) => {
   caselist= (data.showList as any)[item];
}

const handerField = (item: number) => {
   caselist= data.showList [item as keyof typeof data.showList ]
}

const handerField =  function <T extends object, K extends keyof T>(obj: T, key: K) {
  return obj[key];
}