react 报 Uncaught Error: Objects are not valid as a React child (found: object with keys {})

react 报

Uncaught Error: Objects are not valid as a React child (found: object with keys {}). If you meant to render a collection of children, use an array …
今天碰到了一个react报这个错误的；查找了一下 原来是因为在render的时候 没有点上对象的key名字，

比如：` <div className="y-axias">
			            {((item: string, index: number) => (
			              <div className="item" title={item} key={index}>
			                {item}
			              </div>
			            ))}
       </div>`

里面有个项，是对象（‘{}’）；item没有点上对象的key

    可以写成` <div className="y-axias">
			            {((item: string, index: number) => (
			              <div className="item" title={item} key={index}>
			                {item || item[对象的key]}
			              </div>
			            ))}
      		</div>`