/Javascript/React/Conditional Rendering in React js

Conditional Rendering in React js

Ternary react

render() {
  const isLoggedIn = this.state.isLoggedIn;
  return (
    <div>
      The user is <b>{isLoggedIn ? 'currently' : 'not'}</b> logged in.    
	</div>
  );
}

Source: reactjs.org

React native conditional rendering

function Mailbox(props) {
  const unreadMessages = props.unreadMessages;
  return (
    <div>
      <h1>Hello!</h1>
      {unreadMessages.length > 0 &&
        <h2>
          You have {unreadMessages.length} unread messages.
        </h2>
      }
    </div>
  );
}

Source: reactjs.org

React style ternary operator

<img 
  src={this.state.photo} 
  alt="" 
  style={ isLoggedIn ? { display:'block'} : {display : 'none'} }  
/>

// or

<img
  src={this.state.photo} 
  alt=""
  style={ { display: isLoggedIn ? 'block' : 'none' } }  
/>

Conditional Rendering in React js

function UserGreeting(props) {
  return <h1>Welcome back!</h1>;
}

function GuestGreeting(props) {
  return <h1>Please sign up.</h1>;
}

function Greeting(props) {
  const isLoggedIn = props.isLoggedIn;
  if (isLoggedIn) {
    return <UserGreeting />;
  }
  return <GuestGreeting />;
}

ReactDOM.render(
  // Try changing to isLoggedIn={true}:
  <Greeting isLoggedIn={false} />,
  document.getElementById('root')
);

Source: reactjs.org

Similar codes

1 vote363 views2 answers
Push values to state array class react
Javascript React
3 votes311 views1 answer
Include gif in react
Javascript React
4 votes340 views1 answer
Open a new tab when clicking on a link react
Javascript React
105 votes366 views3 answers
React bootstrap do you need to import
Javascript React
1 vote383 views1 answer
Change icon color react native elements
Javascript React
0 vote290 views2 answers
Hide header title in react navigation Drawer navigation
Javascript React
0 vote352 views1 answer
My env.local file not working in my react app usind mac
Javascript React
0 vote302 views1 answer
React native get navigation bar height
Javascript React
2 votes358 views1 answer
React concatenate string and component
Javascript React
1 vote332 views1 answer
React native basic template
Javascript React