conditional rendering reacts code example

Example 1: if else render react

render() {
  const isLoggedIn = this.state.isLoggedIn;
  return (
    

      {isLoggedIn ? (
        
      ) : (
        
      )}
    
  );
}

Example 2: react native conditional rendering

class Component extends React.Component {
	const a = true
	render() {
      return (
    	
          {a == true
           ? ()
           : null
          }
            	
	  )
	}
}

This is staying: if a == true, render a button component. 
Otherwise render null, in other words nothing.

Example 3: react native conditional rendering

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

      
Hello!
      {unreadMessages.length > 0 &&
        

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

Example 4: && in react jsx

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

      
Hello!
      {unreadMessages.length > 0 &&
        

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

const messages = ['React', 'Re: React', 'Re:Re: React'];
ReactDOM.render(
  ,
  document.getElementById('root')
);