React issue: Each child in a list should have a unique "key" prop.

Trying to solve this warning `"Each child in a list should have a unique "key" prop." `on a react.js app, found out that the dinamically generation of the li buttons for paginate does not contains any "key" or method to add a prop key to all the li . Any recomendation? before do it with JS want to know if there is other way.

Thanks.