Conditional Rendering: How to conditionally render components in React, including if/else statements and ternary operators.

In React, conditional rendering is a powerful and versatile tool that allows developers to display different components or elements based on certain conditions. This is particularly useful when we want to create dynamic web applications that can change their content based on user input, API responses, or any other dynamic data.

If/else Statements

One of the most basic ways to conditionally render components in React is by using if/else statements. This approach involves creating a function that returns different components based on a condition that is evaluated at runtime.

For example, we can create a Greeting component that takes a isLoggedIn prop. If isLoggedIn is true, we return a Welcome back! message, otherwise we return a Please sign up. message:

function Greeting(props) {
  const isLoggedIn = props.isLoggedIn;
  if (isLoggedIn) {
    return <h1>Welcome back!</h1>;
  }
  return <h1>Please sign up.</h1>;
}

Ternary Operators

Another way to conditionally render components in React is by using ternary operators. Ternary operators provide a concise way to write if/else statements, which can make our code more readable and easier to maintain.

For instance, we can use a ternary operator to conditionally render the Welcome back! or Please sign up. message based on the isLoggedIn prop:

function Greeting(props) {
  const isLoggedIn = props.isLoggedIn;
  return (
    <div>
      {isLoggedIn ? (
        <h1>Welcome back!</h1>
      ) : (
        <h1>Please sign up.</h1>
      )}
    </div>
  );
}

Ternary operators can also be used to conditionally render attributes, which can come in handy when we want to apply different styles or behaviors to an element based on certain conditions. For example, we can use a ternary operator to conditionally render the Loading... text if the button is disabled:

function Button(props) {
  const {isDisabled, buttonText} = props;
  return (
    <button disabled={isDisabled}>
      {isDisabled ? "Loading..." : buttonText}
    </button>
  );
}

Conclusion

In conclusion, conditional rendering is a powerful technique in React that allows developers to create dynamic and responsive web applications. By using if/else statements and ternary operators, we can conditionally render components or attributes based on certain conditions, which can help us create more flexible and user-friendly interfaces.