How do I implement conditional rendering in class components?

How do I implement conditional rendering in class components?

In React class components, you can use JavaScript expressions to conditionally render elements. For example, you can use an if statement or a ternary operator in the render method.

Can you show me an example using a ternary operator?

Sure! Here's a simple example:

render() {
  return (
    <div>
      {this.state.isLoggedIn ? <h1>Welcome back!</h1> : <h1>Please log in.</h1>}
    </div>
  );
}

What about using if statements instead?

You can use if statements like this:

render() {
  let message;
  if (this.state.isLoggedIn) {
    message = <h1>Welcome back!</h1>;
  } else {
    message = <h1>Please log in.</h1>;
  }
  return <div>{message}</div>;
}

Are there any performance considerations I should be aware of?

Yes, excessive conditional rendering can lead to performance issues. It's best to keep your render method clean and avoid complex logic. Consider using separate components for different states.