how to conditional a ternary operator if the length of an array is lower than zero in react code example

Example 1: 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' } }  
/>

Example 2: login condition if and else in router dom of react jsx

let redirectToUrl;
      if ( not logged in ) //check condition
      {
        redirectToUrl = <Redirect to={loginPage}/>;
      }