Unique Key Warning.

[baratdev]

index.js:1 Warning: Each child in a list should have a unique "key" prop.

how i can resolve this issue where i have to add unique key, I'm pasting my code here please guide me.

<Navigation
activeItemId={location.pathname}
onSelect={({ itemId }) => {
history.push(itemId);
}}
items={[
{
title: "Dashboard",
itemId: "/",
elemBefore: () => ,
},
{
title: "Management",
//itemId: "/management",
elemBefore: () => ,
subNav: [
{
title: "Projects",
itemId: "/about",
elemBefore: () => ,
},
{
title: "Members",
itemId: "/",
elemBefore: () => ,
},
],
},
{
title: "Another Item",
itemId: "/another",
subNav: [
{
title: "Teams",
itemId: "/management/teams",
},
],
},
]}
/>