Style Application

a) CSS Modules:

CSS Modules allow you to write CSS that’s scoped to a specific component, preventing style conflicts across your application.

How to use CSS Modules:

1. Create a CSS file with a .module.css extension, e.g., Button.module.css
2. Import the styles in your component file
3. Use the imported styles as an object

Example:

Button.module.css:

.button {
  background-color: blue;
  color: white;
  padding: 10px 20px;
  border: none;
  border-radius: 5px;
}

Button.js:

import React from "react";
import styles from "./Button.module.css";

function Button({ children }) {
  return <button className={styles.button}>{children}</button>;
}

export default Button;

Key benefits:

• Locally scoped class names
• Reusable styles
• Compatibility with existing CSS workflows

b) styled-components:

styled-components is a CSS-in-JS library that allows you to write actual CSS code to style your components.

How to use styled-components:

1. Install the library: npm install styled-components
2. Import styled-components in your component file
3. Create styled components using the styled object

Example:

import React from "react";
import styled from "styled-components";

const StyledButton = styled.button`
  background-color: blue;
  color: white;
  padding: 10px 20px;
  border: none;
  border-radius: 5px;
`;

function Button({ children }) {
  return <StyledButton>{children}</StyledButton>;
}

export default Button;

Key benefits:

• No class name bugs
• Easier deletion of CSS
• Dynamic styling based on props

2. Apply basic styling to your components

Let’s apply some basic styling to a simple Todo application using both CSS Modules and styled-components.

Using CSS Modules:

TodoApp.module.css:

.container {
  max-width: 500px;
  margin: 0 auto;
  padding: 20px;
  font-family: Arial, sans-serif;
}

.input {
  width: 100%;
  padding: 10px;
  margin-bottom: 10px;
}

.button {
  background-color: #4caf50;
  color: white;
  padding: 10px 20px;
  border: none;
  cursor: pointer;
}

.list {
  list-style-type: none;
  padding: 0;
}

.item {
  background-color: #f1f1f1;
  margin: 5px 0;
  padding: 10px;
  display: flex;
  align-items: center;
}

.checkbox {
  margin-right: 10px;
}

TodoApp.js:

import React, { useState } from "react";
import styles from "./TodoApp.module.css";

function TodoApp() {
  const [todos, setTodos] = useState([]);
  const [input, setInput] = useState("");

  const addTodo = (e) => {
    e.preventDefault();
    if (input) {
      setTodos([...todos, { id: Date.now(), text: input, completed: false }]);
      setInput("");
    }
  };

  const toggleTodo = (id) => {
    setTodos(
      todos.map((todo) =>
        todo.id === id ? { ...todo, completed: !todo.completed } : todo,
      ),
    );
  };

  return (
    <div className={styles.container}>
      <form onSubmit={addTodo}>
        <input
          className={styles.input}
          value={input}
          onChange={(e) => setInput(e.target.value)}
          placeholder="Add a todo"
        />
        <button className={styles.button} type="submit">
          Add
        </button>
      </form>
      <ul className={styles.list}>
        {todos.map((todo) => (
          <li key={todo.id} className={styles.item}>
            <input
              type="checkbox"
              className={styles.checkbox}
              checked={todo.completed}
              onChange={() => toggleTodo(todo.id)}
            />
            <span
              style={{
                textDecoration: todo.completed ? "line-through" : "none",
              }}
            >
              {todo.text}
            </span>
          </li>
        ))}
      </ul>
    </div>
  );
}

export default TodoApp;

Using styled-components:

import React, { useState } from "react";
import styled from "styled-components";

const Container = styled.div`
  max-width: 500px;
  margin: 0 auto;
  padding: 20px;
  font-family: Arial, sans-serif;
`;

const Input = styled.input`
  width: 100%;
  padding: 10px;
  margin-bottom: 10px;
`;

const Button = styled.button`
  background-color: #4caf50;
  color: white;
  padding: 10px 20px;
  border: none;
  cursor: pointer;
`;

const List = styled.ul`
  list-style-type: none;
  padding: 0;
`;

const Item = styled.li`
  background-color: #f1f1f1;
  margin: 5px 0;
  padding: 10px;
  display: flex;
  align-items: center;
`;

const Checkbox = styled.input`
  margin-right: 10px;
`;

function TodoApp() {
  const [todos, setTodos] = useState([]);
  const [input, setInput] = useState("");

  const addTodo = (e) => {
    e.preventDefault();
    if (input) {
      setTodos([...todos, { id: Date.now(), text: input, completed: false }]);
      setInput("");
    }
  };

  const toggleTodo = (id) => {
    setTodos(
      todos.map((todo) =>
        todo.id === id ? { ...todo, completed: !todo.completed } : todo,
      ),
    );
  };

  return (
    <Container>
      <form onSubmit={addTodo}>
        <Input
          value={input}
          onChange={(e) => setInput(e.target.value)}
          placeholder="Add a todo"
        />
        <Button type="submit">Add</Button>
      </form>
      <List>
        {todos.map((todo) => (
          <Item key={todo.id}>
            <Checkbox
              type="checkbox"
              checked={todo.completed}
              onChange={() => toggleTodo(todo.id)}
            />
            <span
              style={{
                textDecoration: todo.completed ? "line-through" : "none",
              }}
            >
              {todo.text}
            </span>
          </Item>
        ))}
      </List>
    </Container>
  );
}

export default TodoApp;

Both these examples achieve similar styling, but with different approaches. CSS Modules keep your CSS separate from your JavaScript, while styled-components allow you to write your styles directly in your component files.

The choice between CSS Modules and styled-components often comes down to personal or team preference, as well as the specific needs of your project.