how to test the if else in return in react js code example

Example 1: adding a if stement in jsx

render() {
    return (   
        
            {this.state.value == 'news'? data: null }
        
    )
}

Example 2: react native conditional rendering

function Mailbox(props) {
  const unreadMessages = props.unreadMessages;
  return (
    

      
Hello!
      {unreadMessages.length > 0 &&
        

          You have {unreadMessages.length} unread messages.
        
      }
    
  );
}