react conditional class with code examples 2

React is one of the most popular JavaScript libraries and is widely used because of its powerful features and flexibility. One of the most commonly used features of React is the conditional class, which can be used to apply different styles to components based on certain conditions. In this article, we’ll explore how to use conditional class in React with code examples.

What is a conditional class in React?

In React, conditional class is a way to apply different CSS classes to a component based on a particular condition. For example, you might want to apply one class when a certain state is true or not. The power of React lies in its ability to react to different states and conditions, and conditional classes are an important feature for making your app more dynamic.

How to use a conditional class in React?

Let’s explore how to use conditional class in React with some code examples. First, we’ll create a basic React component, and then we’ll add a conditional class to it based on some logic.

Step 1: Create a basic React component

import React from 'react';

const App = () => {
  return (
    <div className="container">
      <h1>Welcome to my React App</h1>
      <p>Let's use some conditional classes!</p>
    </div>
  )
}

export default App;

This is a basic React component. We have added a container div, an h1 tag and a p tag inside it. Now, we’ll add a conditional class to the container div based on some logic.

Step 2: Add a conditional class based on state

We can add a conditional class based on the state of the component. Let’s add a state called showText, which will be a boolean value. If the value of showText is true, we’ll add a class called show to the container div. If it’s false, the class won’t be added.

import React, { useState } from 'react';

const App = () => {
  const [showText, setShowText] = useState(false);
  
  return (
    <div className={`container ${showText ? 'show' : ''}`}>
      <h1>Welcome to my React App</h1>
      <p>Let's use some conditional classes!</p>
      <button onClick={() => setShowText(!showText)}>Toggle Text</button>
    </div>
  )
}

export default App;

Here, we have used a template string to concatenate the class name. We have added a class called container and if showText is true, we have also added a class show. We have also added a button that toggles the showText state when clicked.

Step 3: Add a conditional class based on props

We can also add a conditional class based on the props of a component. Let’s create a component called Button that accepts a prop called variant. If the prop is "primary", we’ll add a class called button-primary to the button element. If it’s not, we’ll add a class called button-secondary.

import React from 'react';

const Button = ({ variant }) => {
  return (
    <button className={`button ${variant === 'primary' ? 'button-primary' : 'button-secondary'}`}>
      My Button
    </button>
  )
}

export default Button;

Here, we have used a ternary operator to check the value of variant. If it’s "primary", we have added a class called button-primary. If it’s not, we have added a class called button-secondary.

Step 4: Add multiple conditional classes

Sometimes, we might want to add multiple classes based on different conditions. We can achieve this by using a ternary operator inside a template string.

import React, { useState } from 'react';

const App = () => {
  const [showText, setShowText] = useState(false);
  const [isError, setIsError] = useState(false);
  
  return (
    <div className={`container ${showText ? 'show' : ''} ${isError ? 'error' : ''}`}>
      <h1>Welcome to my React App</h1>
      {isError && <p className="error-text">Something went wrong!</p>}
      <p>Let's use some conditional classes!</p>
      <button onClick={() => setShowText(!showText)}>Toggle Text</button>
      <button onClick={() => setIsError(!isError)}>Toggle Error</button>
    </div>
  )
}

export default App;

Here, we have added two more states called isError and error-text. We have used a template string to add three classes based on different conditions. We have also used a conditional rendering to show an error message if isError is true.

Conclusion

In this article, we have explored how to use conditional class in React with code examples. We have seen how to add a conditional class based on state and props, how to add multiple conditional classes, and how to use conditional rendering to show error messages. Conditional classes are a powerful feature of React, and they can be used to make your app more dynamic and visually appealing.

React Conditional Class with Code Examples

React is an open-source JavaScript library used to build user interfaces. Its popularity is due to its flexibility and powerful features. One of React's essential features is the conditional class, which allows developers to apply different styles to components based on certain conditions. In this article, we’ll dive deeper into using conditional classes in React with code examples.

What is a Conditional Class in React?

Conditional classes are a way of applying different CSS styles to a component based on a specific condition. For instance, we may want to apply a specific class to a component when a user interacts with it. In React, the power of conditional classes comes from the ability to react to different states and conditions, making applications more dynamic and interactive.

Adding Conditional Classes Based on State

Adding conditional classes based on state is one of the most common use cases in React. In this context, we will typically use the useState hook to manage components' state and add classes conditionally. Let's take a look at an example where we add a class based on the state of a button.

import React, { useState } from 'react';

export default function ButtonWithClass() {
  const [buttonState, setButtonState] = useState(false);

  const handleButton = () => {
    setButtonState(!buttonState);
  }

  return (
    <button
      onClick={handleButton}
      className={`button ${buttonState ? 'active' : ''}`}>
      Click Me
    </button>
  );
}

In the example above, we create a component that includes a button which has an initial state of false. When the button is clicked, we toggle the state of the button using the setButtonState function. We then use a template string to add a class to the button. If buttonState is true, we add the class'active' to the button. If not, the class is not added.

Adding Conditional Classes Based on Props

Another way to add conditional classes in React is by using props. This can be useful when you need to apply varying styles to a component based on how the component’s parent is using it. Let's take a look at an example where we want our button component to receive a variant prop and apply a different class based on it.

import React from 'react';
import './Button.css';

export default function Button({variant, children}) {

  return (
    <button 
      className={`button ${variant} `}>
        {children}
    </button>
  )
}

In the example above, we receive a variant prop from the parent component. The variant prop allows us to style our button component differently based on how the parent component decides to use it. Here, we'll add the variant prop to the className of the button component using a template string.

Adding Multiple Conditional Classes

You can also add multiple classes based on different conditions in React. For example, you might want to add a class when a button is clicked to indicate that an action has been performed. You could also add a different class when an error occurs. Here is an example:

import React, { useState } from 'react';

export default function MultipleClasses() {
  const [buttonState, setButtonState] = useState(false);
  const [error, setError] = useState(false);

  const handleButton = () => {
    setButtonState(!buttonState);
  }

  const handleErrors = () => {
    setError(true);
  }

  return (
    <div 
      className={`container ${buttonState ? 'active' : ''} ${error ? 'error' : ''}`}>
      {error && <p className="error-text">An error occurred!</p>}
      <button onClick={handleButton}>Click Me</button>
      <button onClick={handleErrors}>Errors</button>
    </div>
  )
}

In the example above, we have added two different states and used them to add classes conditionally. The buttonState state changes when the button is clicked and adds the active class to the container div. Also, the error state adds an error class to the container div to indicate an error occurred.

Conclusion

Conditional classes are a powerful feature of React that allows developers to create dynamic components. By adding classes conditionally based on state, props, or multiple conditions, we can provide our components with different styles and allow our users to interact with them in a way that reinforces user experience. Implementing Conditional classes in React is usually straightforward, but there are many ways to approach the problem.

Popular questions

  1. What is a conditional class in React?
    A conditional class allows developers to apply different CSS classes to a component based on a particular condition, such as the state or props of the component.

  2. How can we add a conditional class based on state in React?
    We can use the useState hook to manage the state of a component and add a conditional class based on the state using a template string and a ternary operator.

  3. How can we add a conditional class based on the props of a component in React?
    We can add a conditional class based on props by including a prop in the component parameters and using it in a template string with a ternary operator.

  4. Can we add multiple conditional classes using React?
    Yes, we can add multiple conditional classes based on different conditions using a template string and a ternary operator.

  5. What are some use cases for implementing conditional classes in React?
    Conditional classes are useful for improving the user experience in components that respond to user actions, such as buttons and forms. They can also be used to indicate errors or status updates in a component.

Tag

"ReactClassExamples"

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