Most props on a JSX element are passed on to the component, however, there are two special props (`ref` and `key`) which are used by React, and are thus not forwarded to the component.
For instance, attempting to access `this.props.key` from a component (eg. the render function) is not defined. If you need to access the same value within the child component, you should pass it as a different prop (ex: `<ListItemWrapper key={result.id} id={result.id} />`). While this may seem redundant, it's important to separate app logic from reconciling hints.
__Note:__ You will also see this warning if you define `key` or `ref` PropTypes (using [PropTypes typechecking](https://reactjs.org/docs/typechecking-with-proptypes.html#proptypes)).
For instance, attempting to access `this.props.key` from a component (i.e., the render function or [propTypes](https://reactjs.org/docs/typechecking-with-proptypes.html#proptypes)) is not defined. If you need to access the same value within the child component, you should pass it as a different prop (ex: `<ListItemWrapper key={result.id} id={result.id} />`). While this may seem redundant, it's important to separate app logic from reconciling hints.