Warning: Each child in a list have a unique key prop warning

[naskarsubhajit]

It looks that TreeNode component already has implementation like below:
return (

{children.map((child, index) => (
<TreeNode
{...{onToggle, animations, style}}
decorators={propDecorators}
key={child.id || index}
node={child}
/>
))}

still why it gives this warning

[YiJiangFengYun]

This is a problem of the TreeBeard, not of TreeNode.