html5 - ant-design

Question

As shown in the figure, this error is thrown when using ant-design. What does this error mean?

Answer 1

must set key for <rc-animate> children

Answer 2

If you use map or other loops to produce vdom, you must specify a unique key value

Answer 3

Solved. When mode='multiple' in <select> in <formitem></formitem>, if there is an initial value, it must be written as an array.