Flash cards
Review the key moves
What is the main idea behind React Conditional Rendering?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___ MissedGoal() {Put the learning moves in the order that makes the concept easiest to apply.
In React, you can conditionally render components.
There are several ways to do this.
if Statement
We can use the if JavaScript operator to decide which component to render.
We'll use these two components
function MissedGoal() {
return <h1>MISSED!</h1>;
}
function MadeGoal() {
return <h1>Goal!</h1>;
}Example
Now, we'll create another component that chooses which component to render based on a condition:
function Goal(props) {
const isGoal = props.isGoal;
if (isGoal) {
return <MadeGoal/>;
}
return <MissedGoal/>;
}
createRoot(document.getElementById('root')).render( <Goal isGoal={false} /> );Try changing the isGoal attribute to true :
Example
createRoot(document.getElementById('root')).render( <Goal isGoal={true} /> );Logical && Operator
Another way to conditionally render a React component is by using the && operator.
In the example below, the heading will only be rendered if the props.brand property is not empty:
Example
The right side of && will only be rendered if the left side is true:
function Car(props) {
return ( <> {props.brand && <h1>My car is a {props.brand}!</h1>}
</> );
}
createRoot(document.getElementById('root')).render( <Car brand="Ford" /> );If props.brand evaluates to true, the expression after && will render.
Example
createRoot(document.getElementById('root')).render( <Car /> );Ternary Operator
Another way to conditionally render elements is by using a ternary operator.
condition ? true : falseWe will go back to the goal example.
Example
Return the MadeGoal component if isGoal is true , otherwise return the MissedGoal component:
function Goal(props) {
const isGoal = props.isGoal;
return ( <> { isGoal ? <MadeGoal/> : <MissedGoal/> }
</> );
}
createRoot(document.getElementById('root')).render( <Goal isGoal={false} /> );To learn more, see the ternary operator section.