Usually when building complex UIs, you would need to render a component or a React element according to the state or props received.

React components allow JavaScript to be executed within curly brackets and it can be used with the conditional ternary operator to decide which component or React element to render. For instance:

const Meal = ({ timeOfDay }) => (  
    <span>{timeOfDay === 'noon' 
        ? 'Pizza' 
        : 'Sandwich' 
    }</span>  
) 

This also could have been written as:

const Meal = ({ timeOfDay }) => (  
    <span children={timeOfDay === 'noon' 
        ? 'Pizza' 
        : 'Sandwich' 
    } />  
) 

If passing "noon" as the timeOfDay property value, it will generate the following HTML content:

<span>Pizza</span> 

Or the following when the timeOfDay property is not set to "noon":

<span>Sandwich</span>